Wheat Science: Nutritional and Anti-Nutritional Properties, Processing, Storage, Bioactivity, and Product Development 1032293748, 9781032293745

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Wheat Science

Globally, significant work has been done to enhance our current understanding of the nutritional and anti-nutritional properties, processing, storage, bioactivity, and product development of wheat, opening new frontiers for further improvement. Wheat Science: Nutritional and Anti-Nutritional Properties, Processing, Storage, Bioactivity, and Product Development addresses the topics associated with the advances in understanding the wheat biochemical, nutritional, and rheological quality. Improving crop varieties by either conventional breeding or transgenic methods to obtain nutritionally enhanced crops has the advantage of making a one-time investment in research and development to have sustainable products. Features: • Includes topics associated with the nutritional composition and anti-nutritional properties • Addresses the effects of different processing technologies on flour yield and end products • Reviews the effects of storage on nutritional, baking and rheological quality, organoleptic quality, etc. Processing and storage technologies have impacted the nutritional quality and the bioavailability of nutrients in wheat. Due to its peculiar grain protein composition, especially gluten protein, wheat has extensive usage in making numerous end products, eaten round the clock. Researchers have demonstrated a significant effect of alteration of flour-processing technologies on the rheological quality of end products. This book provides a holistic understanding and covers recent developments of wheat science under one umbrella. Emphasis is placed on current trends and advances in nutritional and anti-nutritional properties, processing, storage, bioactivity, and product development. Additionally, efforts have been made to compile the available information on the application of different ingredients of wheat in the industry and pharma sectors.

Cereals: Science and Processing Technology Series Editors: Sneh Punia and Manoj Kumar Maize Nutritional Composition, Processing, and Industrial Uses Edited by Sukhvinder Singh Purewal, Pinderpal Kaur, Sneh Punia, Kawaljit Singh Sandhu, Surender Kumar Singh, and Maninder Kaur

Wheat Science Nutritional and Anti-Nutritional Properties, Processing, Storage, Bioactivity, and Product Development Edited by Om Prakash Gupta, Sunil Kumar, Anamika Pandey, Mohd. Kamran Khan, Sanjay Kumar Singh, and Gyanendra Pratap Singh

For more information about this series, please visit: www.routledge.com/Cereals/ book-series/CSPT

Wheat Science

Nutritional and Anti-Nutritional

Properties, Processing, Storage,

Bioactivity, and Product Development

Edited by Om Prakash Gupta, Sunil Kumar,

Anamika Pandey, Mohd. Kamran Khan,

Sanjay Kumar Singh, and

Gyanendra Pratap Singh

Designed cover image: © ICAR-Indian Institute of Wheat and Barley Research, Karnal-132001, Haryana, India First edition published 2024 by CRC Press 6000 Broken Sound Parkway NW, Suite 300, Boca Raton, FL 33487–2742 and by CRC Press 4 Park Square, Milton Park, Abingdon, Oxon, OX14 4RN CRC Press is an imprint of Taylor & Francis Group, LLC © 2024 selection and editorial matter, Om Prakash Gupta, Sunil Kumar, Anamika Pandey, Mohd. Kamran Khan, Sanjay Kumar Singh, and Gyanendra Pratap Singh; individual chapters, the contributors Reasonable efforts have been made to publish reliable data and information, but the author and publisher cannot assume responsibility for the validity of all materials or the consequences of their use. The authors and publishers have attempted to trace the copyright holders of all material reproduced in this publication and apologize to copyright holders if permission to publish in this form has not been obtained. If any copyright material has not been acknowledged please write and let us know so we may rectify in any future reprint. Except as permitted under U.S. Copyright Law, no part of this book may be reprinted, reproduced, transmitted, or utilized in any form by any electronic, mechanical, or other means, now known or hereafter invented, including photocopying, microfilming, and recording, or in any information storage or retrieval system, without written permission from the publishers. For permission to photocopy or use material electronically from this work, access www.copyright.com or contact the Copyright Clearance Center, Inc. (CCC), 222 Rosewood Drive, Danvers, MA 01923, 978-750-8400. For works that are not available on CCC please contact [email protected] Trademark notice: Product or corporate names may be trademarks or registered trademarks and are used only for identification and explanation without intent to infringe. ISBN: 978-1-032-29374-5 (hbk) ISBN: 978-1-032-31080-0 (pbk) ISBN: 978-1-003-30793-8 (ebk) DOI: 10.1201/9781003307938 Typeset in Times by Apex CoVantage, LLC

Contents

About the Editors ....................................................................................................... vii

List of Contributors ..................................................................................................... xi

Preface ..................................................................................................................... xvii

1 Wheat: Origin, History, and Production Practices ........................................ 1

Sanjay Kumar Singh, Anju Mahendru Singh, Om Prakash Gupta, and

Pradeep Kumar Singh

2 Wheat Production, Trade, Consumption, and Stocks: Global Trends and Prospects .....................................................................................................33 Sendhil R., Kiran Kumara T. M., Ankita Kandpal, Binita Kumari, and

Soumya Mohapatra

3 Pre- and Post-Harvest Management of Wheat for Improving the Productivity, Quality, and Resource Utilization Efficiency ..........................57 Neeraj Kumar, Ganesh Upadhyay, Krishna Bahadur Chhetri, Harsha B. R., Gulshan Kumar Malik, Ravindra Kumar, Poonam Jasrotia, Shiv Ram Samota, Nitesh Kumar, R. S. Chhokar and S. C. Gill 4 Contribution of Wheat in Global Food Security in Changing Climatic Conditions: Challenges Ahead and Coping Strategies ................107 Anil Kumar Dixit, Biswajit Sen, Shweta Bijla, Sanjit Maiti, and Babita Kathayat 5 Nutritional Composition, Bioactive Compounds, and Phytochemicals of Wheat Grains ..............................................................................................125 Akhlash P. Singh 6 Wheat-Based Anti-Nutritional Factors and Their Reduction Strategies: An Overview .................................................................................183 Vanita Pandey, Ajeet Singh, Neha Patwa, Ankush, Om Prakash Gupta, Gopalareddy K., Sunil Kumar, Anuj Kumar, Sewa Ram, and Gyanendra Pratap Singh 7 Wheat Milling and Recent Processing Technologies: Effect on Nutritional Properties, Challenges, and Strategies .....................................219 Manju Bala, Surya Tushir, Monika Garg, Maninder Meenu, Satveer

Kaur, Saloni Sharma, and Sandeep Mann

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Contents

8 Effect of Storage Conditions on the Nutritional Quality of Wheat ............ 257

Nitin Kumar Garg, Chirag Maheshwari, Muzaffar Hasan, Amresh Kumar, Jaipraksh Bisen, Rakesh Kumar Prajapat, Nand Lal Meena, and Om Prakash Gupta 9 Molecular Mechanisms of Major Bioactive Compounds for Human Health Benefits................................................................................................ 269 Arti Kumari, Nand Lal Meena, Prathap V., Jyoti Prakash Singh,

Muzaffar Hasan, Chirag Maheshwari, Rakesh Kumar Prajapat,

Om Prakash Gupta, and Aruna Tyagi

10 Micronutrient Biofortification in Wheat: Status and Opportunities........ 285 Gopalareddy Krishnappa, H. M. Mamrutha, N. D. Rathan, Hanif Khan, C. N. Mishra, Vishnu Kumar, Krishna Viswanatha Reddy, Vanita Pandey, Rinki Khobra, Charan Singh, K. J. Yashavanthakumar, Suma Biradar, B. S. Tyagi, Gyanendra Singh, and Gyanendra Pratap Singh 11 Techno-Functional Properties of Wheat-Based Food Products ................ 303

Rakesh Kumar Prajapat, Megha Sharma, Saurabh Joshi, Mukesh Saran, Nitin Kumar Garg, Nand Lal Meena, and Manas Mathur 12 Gluten-Related Disorders: Current Understanding, Myths, and Facts ....321 Sunil Kumar, Ajeet Singh, Ankush, Akhlash P. Singh, Sewa Ram, Om Prakash Gupta, Vanita Pandey, Hanif Khan, Ramesh Soni, and Gyanendra Pratap Singh 13 Application of Wheat and Its Constituents in Diverse Functional Food Products ..................................................................................................339 Hanuman Bobade, Harmandeep Kaur, and Deep Narayan Yadav 14 Trends and Approaches of Wheat Flour and End-Product Fortification Technologies ..............................................................................373 Rakesh Kumar Prajapat, Manas Mathur, Sarita Kumari, Sumit Kumar, Megha Sharma, Nitin Kumar Garg, Deepak Sharma, and Nand Lal Meena 15 Molecular and Biotechnological Strategies for Improving Nutritional Quality of Wheat .............................................................................................397 Divya Ambati, Rahul M. Phuke, Uday G. Reddy, Rahul Gajghate, Singh J. B., and Sai Prasad S. V. 16 Wheat Biofortification and Mainstreaming Grain Zinc and Iron in CIMMYT Wheat Germplasm .......................................................................421 Velu Govindan, Ravi P. Singh, and Maria Itria Ibba Index.........................................................................................................................429

About the Editors

Dr. Om Prakash Gupta is Senior Scientist (Plant Biochemistry) at ICAR-Indian Institute of Wheat and Barley Research, Karnal, Haryana, India. He obtained his M.Sc. and Ph.D. degrees from ICAR-Indian Agricultural Research Institute, New Delhi. He has been actively engaged in research and teaching in the field of wheat quality and molecular biology since 2008. His major research interests include small RNA’s role during various biotic and abiotic stresses, molecular basis of Fe and Zn biofortification, and nutritional and processing quality. Dr. Gupta has authored and coauthored in more than 80 research publications and served as editorial board member of many peer-reviewed journals. Dr. Gupta is the recipient of several academic awards including Jawaharlal Nehru Award for outstanding doctoral thesis by ICAR, University Silver Medal, Aspee Gold Medal Dr. Kirtikar Memorial Gold Medal, and Chowdhary Charan Singh Memorial Award. He is fellow of the Society for Advancement of Wheat and Barley Research. Dr. Sunil Kumar is currently serving as Principal Scientist (Biochemistry) at Quality and Basic Science Division at ICAR-IIWBR, Karnal. He obtained his M.Sc. and Ph.D. degrees in Biochemistry from CCS Haryana Agricultural University, Hisar, Haryana, India. He has served as Assistant Professor at MPUAT, Udaipur, Rajasthan, India, and as Assistant Scientist at CCSHAU, Hisar, from 2005 to 2011 before joining ICAR as Senior Scientist and con­ tributed toward teaching and research work. His areas of research interest are plant biochemistry, antioxidative sys­ tem and post-harvest biology. Throughout 16  years of service experience, he has worked/completed various institutional/externally funded research projects. He has also served as I/c PC KVK, Fazilka. Dr. Sunil Kumar has 30 research papers (of international and national repute), one edited book, and more than 50 other publications including technical bulletins, book chapters, conference abstracts, practical manuals, and popular articles to his credit. Currently, he is actively involved in processing and enhancing nutritional quality of wheat using biochemical/molecu­ lar approaches, and in wheat-breeding program for high yield and wider adaptability in North Western Plains.

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About the Editors

Dr. Anamika Pandey is currently working in the capacity of Assistant Professor at Department of Soil Science and Plant Nutrition, Faculty of Agriculture, Selcuk University, Turkey. She is also handling a 1001 national project funded by The Scientific and Technological Research Council of Turkey (TUBITAK) related to the determination of novel genes regu­ lating boron toxicity tolerance in some of the Poaceae family species. She earned her Ph.D. degree in biotechnology from India. Her current research focuses on identifying the novel genes and transcriptional factors in wild wheat species, which are responsible for making them tolerant toward different biotic and abiotic stress conditions. With a research experience of 14 years in plant molecular biology, she has published several articles in SCI-indexed journals and is in the editorial and reviewer board of different reputed journals such as PLOS Sustainability and Transformation and BMC Plant Biology. Dr. Mohd. Kamran Khan is presently working as Assistant Professor in Department of Soil Science and Plant Nutrition, Faculty of Agriculture, Selcuk University, Konya, Turkey. He obtained his Ph.D. in Biotechnology from Sam Higginbottom University of Agriculture, Technology and Sciences, Allahabad, India. Dr. Khan has around 14 years of research experience in the area of molecular biology and plant biotechnology. His research is evidenced by his publications in journals of interna­ tional repute like AoB Plants, Frontiers in Plant Science, Plants, Plos One, 3 Biotech, Genetic Resources, and Crop Evolution. He has more than 40 research publications with more than 250 citations including the chapters in the books published from Elsevier and CRC Press Ltd. He is on editorial and reviewer board of different reputed journals such as Plos One, Journal of Applied Genetics, and Scientific Reports. The research interests of Dr. Khan include biochemical and molecular changes in crop plants, especially wheat under different biotic and abiotic stress conditions. He is also interested in looking for the role of nanoparticles in regulating different abiotic stresses in plants. Dr. Sanjay Kumar Singh, an ARS, is Principal Scientist (Plant Breeding) at ICAR-Indian Agricultural Research Institute, Pusa, New Delhi, India. He graduated with silver medal and post-graduated with JS Aggarwal Memorial Gold medal from CSA University of Agriculture and Technology, Kanpur, Uttar Pradesh, India, and doctorate from BHU, Varanasi. He has developed 28 wheat varieties for different agro-ecological con­ ditions of the country and 54 trait specific genetic stocks in wheat. His area of expertise is wheat improvement for abiotic stresses, quality traits and hybrid wheat. He successfully han­ dled 35 research projects funded by CIMMYT-Mexico, DFID-UK, CSIRO-Australia, NFSM, DBT, CSIR, DAC&FW, GoI, ICAR (CRP, AP Cess, NATP, Institute), and DIT, MoC&IT, etc. He has accomplished assignments of Head, IIWBR-Regional Station,

About the Editors

ix

Dalang Maidan, Lahaul and Spiti, Himachal Pradesh, India – a national summer nurs­ ery facility; Zonal Coordinator, Peninsular zone of the AICRP on Wheat and Barley and Nodal Officer, Seed at IIWBR, Karnal. Dr Singh is Chair, Expert Working Group (EWG) on “Breeding Methods & Strategies” of the G-20 Nations Wheat Initiative. He has more than 380 publications of national/ international repute to his credit. He is recipient of several awards including ICAR-Lal Bahadur Shastri Young Scientist Award, 2007; UP-CST Young Scientist Award, 2008; VS Mathur Memorial Award, 2019; and S Nagarajan Memorial Award, 2020, and Fellow-ISGPB, ISPGR, and SAWBAR. He has international exposure as Visiting Scientist to Mexico, the United States, France, the Netherlands, and Morocco. Dr Singh has very close linkages with KVKs, progressive farmers, and seed growers and has trained more than 1,000 farm­ ers/scientists in latest wheat technologies. Dr. Gyanendra Pratap Singh has vast experience in wheat research for more than 25  years. He has developed 37 wheat varieties and 34 genetic stocks suited to different agro-climatic zones of the country. Dr. Singh has published more than 160 research and review papers in reputed peer journals. He is recipient of several prestigious awards such as Rafi Ahmed Kidwai award and BP Pal Gold Medal. He is fellow of many scientific academies and societies such as National Academy of Agricultural Sciences, Indian Society of Genetics and Plant Breeding, Society of Advancement of Wheat Research, and Society for Scientific Development in Agriculture and Technology. He has actively organized several workshops and symposia and chaired many scientific sessions. He is actively involved in mobilization of wheat technologies from laboratory to farmer’s field.

Contributors Divya Ambati ICAR-Indian Institute of Oilseeds Research Rajendranagar, Hyderabad, India Ankush ICAR-Indian Institute of Wheat and Barley Research Karnal, Haryana, India Manju Bala ICAR-Central Institute of Post-Harvest Engineering and Technology, P.O. PAU Ludhiana, Punjab, India Shweta Bijla Directorate of Mushroom Research (DMR) Solan, Himachal Pradesh, India Suma Biradar University of Agricultural Sciences Dharwad, Karnataka, India Jaipraksh Bisen ICAR-National Rice Research Institute Cuttack, Odisha, India Hanuman Bobade Punjab Agricultural University Ludhiana, Punjab, India

Anil Kumar Dixit ICAR-National Dairy Research Institute Karnal, Haryana, India Rahul Gajghate ICAR-Indian Agricultural Research Institute Indore, Madhya Pradesh, India Monika Garg National Agri-Food Biotechnology Institute Mohali, Punjab, India Nitin Kumar Garg Sri Karan Narendra Agriculture University Jobner, Rajasthan, India S. C. Gill ICAR-Indian Institute of Wheat and Barley Research Karnal, Haryana, India Velu Govindan International Maize and Wheat Improvement Center Texcoco, Mexico Om Prakash Gupta ICAR-Indian Institute of Wheat and Barley Research Karnal, Haryana, India

Krishna Bahadur Chhetri Krishi Vigyan Kendra Siwan, Bihar, India

Muzaffar Hasan ICAR-Central Institute of Agricultural Engineering Bhopal, Madhya Pradesh, India

R. S. Chhokar ICAR-Indian Institute of Wheat and Barley Research Karnal, Haryana, India

Maria Itria Ibba International Maize and Wheat Improvement Center Texcoco, Mexico xi

xii Singh J. B. ICAR-Indian Agricultural research Institute Indore, Madhya Pradesh, India Poonam Jasrotia ICAR-Indian Institute of Wheat and Barley Research Karnal, Haryana, India Saurabh Joshi Agriculture University Jodhpur, Rajasthan, India Ankita Kandpal ICAR-National Institute of Agricultural Economics and Policy Research New Delhi, India Babita Kathayat ICAR-National Dairy Research Institute Karnal Karnal, Haryana, India Harmandeep Kaur Punjab Agricultural University Ludhiana, Punjab, India Satveer Kaur National Agri-Food Biotechnology Institute Mohali, Punjab, India Panjab University Chandigarh, Punjab, India

Contributors Gopalareddy Krishnappa ICAR-Indian Institute of Wheat and Barley Research Karnal, Haryana, India ICAR-Sugarcane Breeding Institute Coimbatore, Tamil Nadu, India Amresh Kumar ICAR-National Institute for Plant Biotechnology New Delhi, India Anuj Kumar ICAR-Indian Institute of Wheat and Barley Research Karnal, Haryana, India Neeraj Kumar ICAR-Indian Institute of Wheat and Barley Research Karnal, Haryana, India Nitesh Kumar ICAR-Indian Institute of Wheat and Barley Research Karnal, Haryana, India Ravindra Kumar ICAR-Indian Institute of Wheat and Barley Research Karnal, Haryana, India Sumit Kumar Dr. Rajendra Prasad Central Agricultural University Pusa, Samastipur, Bihar, India

Hanif Khan ICAR-Indian Institute of Wheat and Barley Research Karnal, Haryana, India

Sunil Kumar ICAR-Indian Institute of Wheat and Barley Research Karnal, Haryana, India

Rinki Khobra ICAR-Indian Institute of Wheat and Barley Research Karnal, Haryana, India

Vishnu Kumar ICAR-Indian Institute of Wheat and Barley Research Karnal, Haryana, India

xiii

Contributors Arti Kumari ICAR-Indian Agricultural Research Institute New Delhi, India Binita Kumari Rashtriya Kishan (PG) College Shamli, Uttar Pradesh, India Sarita Kumari Dr. Rajendra Prasad Central Agricultural University Pusa, Samastipur, Bihar, India Kiran Kumara T. M. ICAR-National Institute of Agricultural Economics and Policy Research New Delhi, India Chirag Maheshwari ICAR-Indian Agricultural Research Institute New Delhi, India Sanjit Maiti ICAR-National Dairy Research Institute Karnal Karnal, Haryana, India Gulshan Kumar Malik Indian Institute of Technology Kharagpur, West Bengal, India H. M. Mamrutha ICAR-Indian Institute of Wheat and Barley Research Karnal, Haryana, India Sandeep Mann ICAR-Central Institute of Post-Harvest Engineering and Technology, P.O. PAU Ludhiana, Punjab, India

Manas Mathur Suresh Gyan Vihar University Jaipur, Rajasthan, India Nand Lal Meena ICAR-Indian Agricultural Research Institute New Delhi, India ICAR-National Bureau of Plant Genetic Resources New Delhi, India Maninder Meenu National Agri-Food Biotechnology Institute Mohali, Punjab, India C. N. Mishra ICAR-Indian Institute of Wheat and Barley Research Karnal, Haryana, India Soumya Mohapatra ICAR-National Dairy Research Institute Karnal, Haryana, India Vanita Pandey ICAR-Indian Institute of Wheat and Barley Research Karnal, Haryana, India Neha Patwa Kurukshetra University Kurukshetra, Uttar Pradesh, India Rahul M. Phuke ICAR-Central Institute for Cotton Research Nagpur, Maharashtra, India Rakesh Kumar Prajapat Suresh Gyan Vihar University Jaipur, Rajasthan, India

xiv Harsha B. R. Krishi Vigyan Kendra Siwan, Bihar, India Sendhil R. Pondicherry University Kalapet, Puducherry, India Sewa Ram ICAR-Indian Institute of Wheat and Barley Research Karnal, Haryana, India N. D. Rathan ICAR–Indian Agricultural Research Institute New Delhi, India Krishna Viswanatha Reddy ICAR–Central Tobacco Research Institute Rajahmundry, Andhra Pradesh, India Uday G. Reddy University of Agricultural Sciences Dharwad, Karnataka, India Shiv Ram Samota ICAR-Indian Institute of Wheat and Barley Research Karnal, Haryana, India Mukesh Saran Manipal University Jaipur Jaipur, Rajasthan, India Biswajit Sen ICAR-National Dairy Research Institute Karnal Karnal, Haryana, India Deepak Sharma Jaipur National University Jaipur, Rajasthan, India Megha Sharma University of Rajasthan Jaipur, Rajasthan, India

Contributors Saloni Sharma National Agri-Food Biotechnology Institute Mohali, Punjab, India Ajeet Singh ICAR-Indian Institute of Wheat and Barley Research Karnal, Haryana, India Akhlash P. Singh GGDSD College Chandigarh (Panjab University) Chandigarh, Punjab, India Anju Mahendru Singh ICAR-Indian Agricultural Research Institute PUSA, New Delhi, India Charan Singh ICAR-Indian Institute of Wheat and Barley Research Karnal, Haryana, India Gyanendra Singh ICAR-Indian Institute of Wheat and Barley Research Karnal, Haryana, India Gyanendra Pratap Singh ICAR-Indian Institute of Wheat and Barley Research Karnal, Haryana, India Jyoti Prakash Singh ICAR-National Bureau of Agriculturally Important Microorganisms (NBAIM) Mau, Uttar Pradesh, India Pradeep Kumar Singh ICAR-Indian Agricultural Research Institute New Delhi, India Ravi P. Singh International Maize and Wheat Improvement Center Texcoco, Mexico

xv

Contributors Sanjay Kumar Singh ICAR-Indian Agricultural Research Institute PUSA, New Delhi, India

Ganesh Upadhyay CCS Haryana Agricultural University Hisar, Haryana, India

Ramesh Soni Govt. National P. G. College Sirsa, Haryana, India

Prathap V. ICAR-Indian Agricultural Research Institute New Delhi, India

Surya Tushir ICAR-Central Institute of Post-Harvest Engineering and Technology, P.O. PAU Ludhiana, Punjab, India Aruna Tyagi ICAR-Indian Agricultural Research Institute, New Delhi, India B. S. Tyagi ICAR-Indian Institute of Wheat and Barley Research Karnal, Haryana, India

Sai Prasad S. V. ICAR-Indian Institute of Rice Research Rajendranagar, Hyderabad, India Deep Narayan Yadav ICAR-Central Institute of Post-Harvest Engineering and Technology Ludhiana, Punjab, India K. J. Yashavanthakumar Agharkar Research Institute Pune, Maharashtra, India

Preface

Wheat (Triticum aestivum L.) is the primary staple food crop providing the bulk of food calories (50%), at least 30% of Fe and Zn intake and 20% dietary energy and protein consumption worldwide; thus, it is essential to improve its nutritional quality. With the prediction that world’s population is expected to reach nine billion by 2050, the wheat yield needs to increase by over 60% along with nutritional characteristics with the available arable land. Under this challenging scenario, the emphasis must be toward improvement in productivity and adaptation to environmental challenges. The Consultative Group on International Agricultural Research (CGIAR) has predicted that the average global wheat yields will need to increase to approximately 5 tonnes per ha from the current average of 3.3 tonnes per ha by 2050. This cereal grain can be stored for future use under specified conditions for a prolonged time without impact­ ing the nutritional profile. Though wheat is rich in carbohydrates, fiber, protein, phy­ tochemicals, and antioxidants, it falls short in certain constituents like iron and zinc and essential amino acid like lysine. Such deficiencies, sometimes, are associated with malnutrition, if not supplemented by other sources, resulting in complex health issues and disturbance of socioeconomic balance. Fortification and biofortification-based approaches can extend a fruitful approach in alleviating micronutrient deficiencies. With a range of functionally existent ploidy levels starting from 2n (monococcum), 4n (durum) to 6n (aestivum), wheat has a diverse species range, though majority of today’s cultivation is restricted to aestivum with a minor cultivation of durums. Such complexity of genome makes biotechnological and molecular refinement of wheat crop very challenging. Over the period, significant research works have been done to understand the sci­ ence of wheat quality involving processing, biochemical, rheological, nutritional, molecular, and biotechnological tools; globally, however, the knowledge is scattered. Therefore, this book on “Wheat Science” presents an effort to encompass the arena of wheat breeding, agronomy, quality, processing, nutritional quality, storage, bio­ technology, and health-related aspects of wheat. It entails production practices, trade, consumption, buffer stock, and management of wheat throughout the world. In initial few chapters, we have covered the role of wheat in global food security along with its nutritional and phytochemical profile. In mid-section, we have discussed the effect and impact of storage, milling, and processing on nutritional quality of wheat followed by molecular mechanisms of bioactive compounds on human health. The book also touches upon the role of fortification and biofortification toward micronutrient enrich­ ment in wheat grains and associated processed products and their techno-functional properties. The scope of biotechnological and molecular approaches in improving nutritional qualities along with gluten-related disorders has also been discussed in brief. Therefore, this book shall provide a milestone to break untrodden intricacies of wheat improvement program on multiple aspects of wheat science benefitting differ­ ent wheat stakeholders, including scholars, students, teachers, researchers, specialists,

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food scientist, cereal biochemists, policy makers, molecular breeders and biologists, biotechnologists, academicians, and professionals working in the area of wheat quality enhancement. Editors Dr. Om Prakash Gupta Senior Scientist (Plant Biochemistry), Division of Quality and Basic Sciences, ICAR-Indian Institute of Wheat and Barley Research, Karnal, Haryana, India Dr. Sunil Kumar Principal Scientist (Plant Biochemistry), Division of Quality and Basic Sciences, ICAR-Indian Institute of Wheat and Barley Research, Karnal, Haryana, India Dr. Anamika Pandey Assistant Professor, Department of Soil Science and Plant Nutrition, Selcuk University, Konya, Turkey Dr. Mohd. Kamran Khan Assistant Professor, Department of Soil Science and Plant Nutrition, Selcuk University, Konya, Turkey Dr. Sanjay Kumar Singh Principal Scientist (Plant Breeding), Division of Genetic, ICAR-Indian Agricultural Research Institute, New Delhi, India Dr. Gyanendra Pratap Singh Director, ICAR-National Bureau of Plant Genetic Resources, New Delhi, India

1 Wheat Origin, History, and Production Practices Sanjay Kumar Singh, Anju Mahendru Singh, Om Prakash Gupta, and Pradeep Kumar Singh CONTENTS 1.1 1.2 1.3 1.4 1.5 1.6

Introduction........................................................................................................ 1

Origin ................................................................................................................. 4

Wheat Research in India.................................................................................... 7

Production Zones and Conditions...................................................................... 8

Varietal Spectrum ............................................................................................ 10

Wheat Production Technology......................................................................... 10

1.6.1 Soil Testing .......................................................................................... 10

1.6.2 Field Preparation ................................................................................. 11

1.6.3 Seed Rate and Treatment..................................................................... 12

1.6.4 Sowing Time and Method ................................................................... 12

1.6.5 Fertilizer Application .......................................................................... 12

1.6.6 Irrigation Management........................................................................ 13

1.6.7 Weed Management .............................................................................. 13

1.6.8 Crop Protection Measures ................................................................... 14

1.6.9 Harvesting, Threshing, and Storage .................................................... 14

1.7 Emerging Challenges ....................................................................................... 14

1.8 Priorities in Wheat Improvement..................................................................... 15

1.9 Approaches in Wheat Improvement ................................................................ 15

1.10 Conclusion........................................................................................................ 17

References.................................................................................................................. 19

1.1 Introduction Wheat (Triticum species) is one of the universal cereals of old world agriculture (Zohary and Hopf, 2000) and the world’s foremost crop plant (Feldman et al., 1995; Gustafson et  al., 2009), which represents a large part of the history of agriculture itself besides its ancestry (Heun et al., 1997; Lev-Yadun et al., 2000; Salamini et al., 2002; Charmet, 2011; Riehl et al., 2013; Bilgic et al., 2016). In prehistoric times, it was cultivated throughout Europe and was one of the most valuable cereals of ancient Persia, Greece, and Egypt. According to Paleo-botanists and archaeologists, the mod­ ern domesticated form of wheat was originated in South-eastern Anatolia, around DOI: 10.1201/9781003307938-1

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Wheat Science

the region of Diyarbakir Province in present-day Turkey at about 8500 bc. In India, evidence from Mohenjo-daro excavations showed wheat cultivation over 5,000 years ago. Presently, wheat makes up a significant part of the world’s diet and provides about one-fifth of the calories and proteins used by humans, making it the second-most important staple, after rice (Dubcovsky and Dvorak, 2007; Shewry, 2009; Hawkesford et  al., 2013; Shiferaw et  al., 2013; Chakraborty et  al., 2020). Wheat grain contains 60–80% carbohydrates mainly as starch, 8–15% proteins, 1.5–2.0% fats, 2–3% crude fibres, 1.5–2.0% minerals, and traces of vitamins with 11% water and provides about 340 calories of energy (Shewry and Hey, 2015). Nearly 55% of carbohydrates intake and 20% of food calories consumed in the world are attributed to wheat (Breiman and Graur, 1995). Asia represents the largest share (58%) of the culinary uses of wheat, followed by Europe (18%), but the per capita consumption is quite low, that is, 63.62 kg per annum, compared to other continents of the world (FAO, 2011). Wheat is extensively grown on 17% of all crop areas, in the temperate, Mediterraneantype, and subtropical parts of both hemispheres at wide range of altitudes, from 67° N in Norway, Finland, and Russia to 45°S in Argentina (Feldman, 1995). Wheat is the second-most important cereal crops globally and contributes about one-third of grain production, but it remains the largest cultivated and traded cereal in the world among all crops (OECD-FAO, 2020). In 2020, more than 760.9 million tonnes (mt) of wheat were produced on 219 million hectares around the world with a productivity of 3.47 tons/ha, and estimates indicated 0.33% increase in global wheat production in 2020– 21 by producing 778.63 million metric tons (Statistica, 2022; USDA, 2022). Regional share of wheat in global production indicated largest contribution of 45.7% and 33.5% by Asia (347.92 mt) and Europe (255.02 mt), respectively, to the global wheat basket (FAOSTAT, 2020). Although wheat is produced in over 123 countries, but the EU, China, India, Russia, the United States, Australia, Ukraine, Pakistan, Canada, and Argentina, the top ten wheat-producing countries (Figure 1.1), contribute over 82% of total wheat production (FAOSTAT, 2020). Production trends indicated roughly equal split of wheat production between the developing and developed world where the developing regions including China and Central Asia account for roughly 53% of the total harvested area and 50% of the

160 140 120 100 80 60 40 20 0

138.42

136.95

109.59 75.16 44.79

36.3

33

FIGURE 1.1 Top ten wheat-producing countries during 2020–21.

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21.65

21

Wheat

3

global production (Shiferaw et al., 2013). China and India together contribute more than 70% of total wheat production in Asia. Current estimates of wheat production showed a dip of approximately 1.06% of global wheat production of 770.3 mt during 2021–22 (FAO, 2021). India produced 109.59 million tons of wheat from 31.1 m ha area during 2020–21 and contributed about 34% to the total food grain production in India (DAC&FW, 2021). The major wheat-growing states in India are Uttar Pradesh, Punjab, Haryana, Madhya Pradesh, Rajasthan, and Bihar which contribute approxi­ mately 91.5% of India’s wheat produce. The average yield trends for wheat indicated higher yield levels in Europe (4.13 tons/ha) than the global average of 3.47 tonnes/ha (t/ha), whereas yield levels in North America (3.45 t/ha) and Asia (3.42 t/ha) are close to global wheat average yield (FAOSTAT, 2020). The country-wise yield levels showed over 8.0 tons/ha yield levels in the top yielding countries New Zealand (8.96 t/ha), the Netherlands (8.61 t/ha), Belgium (8.49 t/ha), and Ireland (8.37 t/ha). However, the average yield of 3.44 t/ha in India is close to the world average yield. The trend of area, production, and pro­ ductivity showed a significant quantum jump in wheat in post-independence period in India where increments of 2.23 times in area under wheat (+21.91 mha: 222.50%), 15.49 times in wheat production (+102.15 mt: 1548.73%), and 4.11 times in wheat pro­ ductivity (+2754 kg/ha: 411.23%) were recorded (Singh et al., 2022). This gargantuan jump in production, post-independence, is attributed to the increased crop productiv­ ity followed by area. Precisely, the impact was more evident since the inception of the All India Coordinated Research Project leading to semi-dwarf wheat-based Green Revolution. Despite of recent risks of climate change, decade-wise analysis indicated increasing trends in area, production, and productivity in recent decades. The wheat is widely adopted by mankind owing to its high environmental adapt­ ability because of its allopolyploid nature and, thereby, genomic plasticity in addition to its excellent food/feed qualities regarding carbohydrates, proteins, vitamin content, and unique elastic property of its gluten, which make it suitable for more diverse use of its flour (Dubcovsky and Dvorak, 2007). Approximately 95% of wheat cultivated is hexaploid with the remaining 5% being durum wheat (T. turgidium L.) and few other less important types (Shewry, 2009). Global production is struck with the primary challenge to produce more food for the burgeoning population due to productivity going towards stagnation in most of the wheat-growing areas. The demand for wheat is expected to increase by 60% by 2050 from the present level for which at least 1.6% per annum increase in wheat yield is required (GCARD, 2012; Wheat Initiative, 2013; Fischer et al., 2014; FAO, 2017; Poudel and Poudel, 2020). During the Green Revolution, the gains in crop productivity were driven by an increased availability of hybrid seeds and fertilizer. The major concern nowadays is declining crop productivity in some countries, which is as high as 25% per year (Rajaram, 2012). For wheat, in spite of the declining growth rate in yield, the overall yields are closer to 1.5% per annum and are able to meet the demand of the world’s growing population (Mittal, 2022). Modernization of agriculture and high external input use in wheat cultivation made total factor productivity (TFP) a more reliable indicator of crop productivity than crop yields. Studies have shown plateaued technical efficiency over the years in predomi­ nated rice–wheat cropping system particularly in South Asia where high input usage, resource degradation and decelerating TFP being the norm for wheat cultivation (Mittal and Kumar, 2000; Kumar et al., 2004; Kumar and Mittal, 2006; Karim and Talukder, 2008; Bhushan, 2016; Ali et al., 2017), the degradation of resource base and

4

Wheat Science

progressive intensification of grain cultivation attributed to the deceleration of TFP growth rates which have been further driven down due to climate change in recent years (Ali and Byerlee, 2002; Byerlee et al., 2003; Hughes et al., 2017). The shrink­ ing resources and environmental conditions in present climate change era necessi­ tate focused efforts to increase yields, resistance to biotic and abiotic stresses, and improved climate-smart agronomic practices for high-input use efficiency and thereby sustainable crop production (Pingali, 1999; Mittal and Lal, 2001; Kumar et al., 2008).

1.2 Origin As a globally cultivated allopolyploid crop, bread wheat has been shaped for suc­ cess by multiple steps of domestication and polyploidization (Pont and Salse, 2017; Glemin et al., 2018). Taxonomically, bread wheat (Triticum aestivum L.), also known as common wheat, is an annual, predominantly autogamous species belonging to the Dinkel section in genus Triticum L. of the tribe Triticeae of the family Gramineae. The tribe Triticeae of the family Gramineae is economically the most important of the grass family, as it contains numerous important crop and forage species (wheat, barley, rye, and others). Wild wheats are commonly divided into two sub-groups: goat grasses in the genus Aegilops L. and wild wheats in the genus Triticum L. All culti­ vated wheats are included in the genus Triticum. Further, wild species in Aegilops and Triticum occur in a polyploid series, based on a haploid number of n = x = 7 chro­ mosomes. Diploid (2x), tetraploid (4x) and hexaploid (6x) species of Aegilops occur naturally, whereas wild species of Triticum occur only at the diploid and tetraploid levels. Cultivated wheat exists at the diploid, tetraploid and hexaploid levels. Percival (1921) categorised into 11 species (Table 1.1), and later Feldman and Sears (1981) have listed 13 diploid, 12 tetraploid, and 5 hexaploid species of Triticum. Recently, taxono­ mists have recognized 24 wild species of Aegilops including weedy A. mutica Boiss and four wild and two domesticated species, for a total of six in the genus Triticum (Slageren, 1994). TABLE 1.1 Different Species of Genus Triticum Species

Common Name

T. monococcum L. T. dicoccum Schubl. T. orientale mihi. T. durum Desf. T. polonicum l. T. turgidum L. T. pyramidale mihi. T. vulgare host. T. compactum Host. T. sphaerococcum mihi. T. spelta L.

Einkorn wheat Emmer wheat Khorasan wheat Macaroni wheat Polish wheat Rivet or Cone wheat Egyptian cone wheat Bread wheat Club wheat Indian dwarf wheat Large spelt or Dinkel wheat

Source: Percival (1921)

5

Wheat TABLE 1.2 Centres of Origin of Triticum Species Species

Common Name

Centre of Origin

T. aestivum T. compactum T. sphaerococcum T. dicoccum T. durum

Bread wheat Club wheat Shot wheat Emmer wheat Durum wheat

T. turgidum

Rivet or cone wheat

T. monococcum

Einkorn wheat

Central Asia, The Near East Central Asia Central Asia Abyssinia The Near East, Mediterranean, Abyssinia The Near East, Mediterranean, Abyssinia The Near East

Source: Zeven and Zhukovskyii (1975), Hawkes (1982)

According to the earliest historic records, wheat was an important cultivated cereal in South Western Asia, its geographical centre of origin. Many wild species of Triticum are found in Lebanon, Syria, northern Israel, and eastern Turkey. Wheat was cultivated in ancient Greece and Egypt in prehistoric times. The Central Asia, Near East, Mediterranean, and Abyssinia regions are the world centres of diversity for wheat and its related species (Table 1.2). Bread wheat is an allohexaploid species, composed of 21 chromosome pairs orga­ nized in three subgenomes, A, B, and D, Genome BBAADD, 2n = 6x = 42 (Sears, 1952). The three genomes of bread wheat (A, B, and D) are derived from three dip­ loid wild ancestors (Blake et al., 1999; Petersen et al., 2006; Marcussen et al., 2014; El-Baidouri et al., 2017), Triticum urartu (AuAu, 2n = 2x = 14), an unknown member of the Sitopsis section (closely related to Aegilops speltoides, BB, 2n = 2x = 14), and Aegilops tauschii (DD, 2n = 2x = 14). Apparently, the diploid, tetraploid, and hexa­ ploid wheat species had all undergone domestication before they were widely culti­ vated. These three genomes were combined through two sequential polyploidization events (Feldman et al., 1995; Huang et al., 2002) as represented in Figure 1.2. The first polyploidization occurred between T. urartu (contributing the A genome) and the Sitopsis species (source of the B genome) about 500,000–150,000 years ago, resulting in the appearance of tetraploid wild emmer wheat (Triticum turgidum ssp. dicoccoi­ des) belonging to the emmer wheat section (Chalupska et al., 2008; IWGSC, 2014; IWGSC, 2018). The egg donor in this initial hybridization event was the donor of the B genome, and the pollen donor contributed the A genome. A domestication of wild tetraploid emmer wheat resulted in the sequential appearance of hulled domesticated emmer wheat (Triticum turgidum ssp. dicoccum) and large-seeded, free-threshing durum wheat (Triticum turgidum ssp. durum) (Dubcovsky and Dvorak, 2007; Avni et al., 2017). Because of its favourable large-seed and free-threshing traits, tetraploid durum wheat had become the major wheat crop by approximately 3,000 years ago. About 10,000 years ago, a second polyploidization event followed the natural hybrid­ ization between the domesticated tetraploid emmer wheats (AABB) and Ae. tauschii (DD), finally giving rise to modern allohexaploid bread wheat T. aestivum (Peng et al., 2011; Dvorak et al., 2012; Wang et al., 2013; Pont et al., 2020; Yao et al., 2020) prob­ ably in the Fertile Crescent region that nowadays comprises Northern Iran (Zohary et al., 2012). It is believed that this event of second polyploidization occurred when the

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Wheat Science

Aegilops speltoids

Triticum urartu

1st polyploidization

T. turgidum ssp. dicoccoides

T. turgidum ssp dicoccum

T. turgidum ssp durum

Dicoccum & Durum Wheat

2nd Polyploidization

Triticum turgidum

dicoccum

Aegilops tauschii

T. aestivum

spelta

T. aestivum

aestivum

FIGURE 1.2 Origin of bread wheat.

cultivation of domesticated emmer wheat spread into the natural range of Ae. tauschii (Salamini et al., 2002). From its origins in the Near East, farming expanded through­ out Europe, Asia, and Africa, together with various domesticated plants and animals. After domestication and centuries of cultivation and selection, this T. aestivum exhib­ ited broader adaptability and many other favour able agronomic traits, which enabled

Wheat

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it to expand further than durum to become the most important cultivated wheat crop worldwide (Kihara, 1944; McFadden and Sears, 1946; Dubcovsky and Dvorak, 2007; Salse et al., 2008; El Baidouri et al., 2017; Pont and Salse, 2017).

1.3 Wheat Research in India Wheat grown in India prior to 20th century was mostly consisted of mixtures of vari­ ous botanical forms usually referred to as ‘sorts’ among which Sharbati, Dara, Safed Pissi, Chandausi, Karachi, Choice White, Hard Red Calcutta, Lal Kanak, Lal Pissi Jaipur Local, Kharchia Local, Mondhya 417, Muzaffar Nagar White, Buxar White, etc., were some prominent local bread wheat sorts utilized nationally and internation­ ally. Sir Albert Howard and his wife Lady G.L.C. Howard initiated systematic bread wheat improvement work in 1905 at Imperial (now Indian) Agricultural Research Institute (IARI) at Pusa in Bihar. Later, wheat improvement was also undertaken at government agricultural colleges at Lyallpur (now in Pakistan), Kanpur, Sabour, Pawarkheda (Madhya Pradesh), Nagpur, Akola, and Niphad (Maharashtra). In the era of pre-semi dwarf bread wheat varieties (1905–62), selection from the mixtures resulted in some important purelines like NP4, NP6, NP12, NP22, Type9, Type11, Pb type8A, C13, C46, AO13, AO49, AO68, AO69, AO85, AO88, and AO90. Some of these varieties earned international recognition due to their excellent grain appear­ ance and are still considered to be valuable genetic resource. Hybridization among these varieties and the exotic wheats was utilized in wheat breeding from the early years of the 20th century which resulted in varieties like NP52, NP80–5, NP120, NP165, NP710, NP770, NP783, NP824, PbC518, PbC591, Niphad4, and AO113. Exotic sources such as Ridley, Padova I, and Padova II gained acceptance, and Federation 41, Kononso, Thatcher, Kenya C 10854, Kenya 48F, Democrat, Spalding’s, Ridit, Reliance, prolific, Gabo, Timstein, Bobin, Gaza, and Regent contributed sig­ nificantly in the Indian wheat breeding programme as donor lines for incorporat­ ing rust resistance led to development of disease-resistant cultivars like K53, K54, RS31–1 and Kenphad25. The varieties developed until early 1960s were tall in stat­ ure and prone to lodging and, therefore, non-responsive to high fertilizer usage, for example, K 65, K 68, and Hyb 65. Similar to those of bread wheat improvement programme, the durum improvement was initiated by H.M. Chibber in 1918–19 in the erstwhile Bombay Presidency by making single plant selections out of the cultivated landraces like Bansi, Kathia, Gangajali, Haura, Jalalia, Jamli, Khandwa, and Malvi. These selections yielded superior lines like Bansi 103, Bansi 162, Bansi 168, Bansi 224, and Baxi 228–18. The durum wheat evolved in India is good source of genes for drought and heat tolerance, and it is mostly used as chapati or dalia due to their unique quality characteristics. Subsequent efforts using exotic germplasm can lead to the development of improved durums like A 206, A 624, Amrut, N 59, NP 404, A-9-30-1, N 5749, Hybrid 23, Ekdania 69, Narasingarh 111, Bijaga yellow, and Bijaga red (Singh et al., 2006b). The real breakthrough in productivity occurred from the introduction of the Norin (having Rht dwarfing gene)-based semi-dwarf Mexican wheat varieties, viz, Lerma Rojo 64-A, Sonora 63, Sonora 64, and Mayo 64 in the early 1960s, possessing a unique set of high productivity traits such as non-lodging habit, high fertilizer responsiveness, and resistance to rust and foliar diseases. Among these, Lerma Rojo 64-A and Sonora

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Wheat Science

64 carrying the genes for dwarfism and resistance to rusts were released by the Central Varietal Release Committee in 1965 which laid the foundation for increased wheat production. At the same time, the establishment of the All India Coordinated Wheat Improvement Project (AICWIP) in 1965 was an important milestone for systematic developments in wheat research resulting in a major breakthrough in wheat produc­ tion and productivity. Later on, the advanced lines from CIMMYT provided the base material for development and commercial release of important amber-coloured vari­ eties, namely, S227 (Kalyansona), S307, S308 (Sonalika), S331, Chhoti Lerma, and Safed Lerma which became the harbingers of the ‘Green Revolution’ in India. During the Green Revolution, yields increased dramatically year on year following the intro­ duction of reduced height alleles which not only increased the harvest index but also allowed the application of more nitrogen without crop lodging (Hawkesford et  al., 2013). The unprecedented growth in the productivity of wheat achieved through the Green Revolution in many developing regions of Asia, Africa, and Latin America has helped overcome famines and has saved millions of lives, and, because of this, wheat is often described as the ‘Miracle Crop’ of the 20th century. This growth in productivity was made possible through technological achievements in developing the semi-dwarf, high yielding varieties and favourable policy and institutional sup­ port in ensuring farmer access to new seeds, fertilizers, markets, and irrigation infra­ structure (Datt and Ravallion, 1998; Fan and Hazell, 2001; Evenson and Rosegrant, 2003; Renkow and Byerlee, 2010). After the initial impact of the Green Revolution in high production zones through the exploitation of  Rht-B1  and  Rht-D1  dwarfing genes in conjunction with disease resistance (Reynolds and Borlaug, 2006), hybrid­ izations between Mexican and Indian varieties led to the release of WL711, HD2009, WH147, HD1982, UP262, HUW12, HD2189, NI5439, and many others which took the wheat revolution to newer heights. Varieties such Lok1, HUW234, HD2285, HD2329, HD2189, and some derivatives of Veery of CIMMYT, viz., HUW206 and HS207, were very popular among the farmers during 1980s. The development of wheat varieties CPAN3004, WH542, PBW343, and PBW373 having 1B/1R transloca­ tion through the utilization of winter wheat gene pool provided a quantum jump in wheat productivity by way of resistance to diseases, enhanced morpho-physiological traits, and wider adaptability. Later, HD2687, UP2338, RAJ3765, K9107, NW1014, HP1744, GW273, GW322, GW366, and MACS2496 covered significant wheat acre­ age in different parts of the country. During early 2000s, PBW 343 was the dominant wheat variety, and, after its susceptibility to yellow rust, DBW17 caught the farmers’ attention as a suitable replacement for PBW343 in NWPZ. The release of landmark varieties PBW343, DBW17, HD2967, and HD3086 brought out a revolution in the high productive environments of northern India. The robust and tall plant types with thick stem has led to a change in the plant type of the varieties with the newer genotypes being more efficient and adaptive. Recent releases DBW187, DBW222, and DBW303 have revolutionized the wheat cultivation in the breadbasket of India with a yield potential of more than 8.0 tons/ha.

1.4 Production Zones and Conditions Wheat in India is cultivated in almost every state except Kerala, thus representing diverse crop growing conditions and situations. Wheat cultivation in India extends

Wheat

9

from 9ºN (Palni hills) to above 35ºN (Srinagar valley of Jammu and Kashmir); thus, the wheat crop is exposed to a wide range of agro-climatic changes such as humid­ ity, temperature, and photoperiod during crop season, soil types, altitudes, latitudes, and cropping systems. Based on the production conditions, India is divided into five mega wheat-producing zones, namely Northern Hills Zone (0.82 mha), North Western Plain Zone (12.33 mha), North Eastern Plain Zone (8.85 mha), Central Zone (6.84 mha), and Peninsular Zone (0.71 mha). NWPZ, NEPZ, and Central Zones are the main contributors to wheat production where approximately 91.5% of the total wheat production comes from states of Uttar Pradesh, Punjab, Haryana, Madhya Pradesh, Rajasthan, and Bihar. Food security of India largely depends on the highest wheatproducing zone of the country NWPZ, comprising Punjab, Haryana, Delhi, western Uttar Pradesh, Tarai regions of Uttarakhand, Jammu and Kathua districts of Jammu and Kashmir, and Una district and Paonta valley of Himachal Pradesh. North Eastern Plain Zone (NEPZ) includes Eastern Uttar Pradesh, Bihar, Jharkhand, Odisha, West Bengal, Assam, and Plains of North Eastern states. There is a large possibility to increase wheat production in this zone which is referred as ‘the sleeping giant’; there­ fore, there is a need that farmers of this zone adopt improved wheat production tech­ nologies to have better harvest. In the central zone, wheat is cultivated in 6.84 mha area of Madhya Pradesh, Chhattisgarh, Gujarat, Kota Udaipur region of Rajasthan, and Bundelkhand region of Uttar Pradesh. Although the average productivity of cen­ tral zone is very less as compared to Punjab and Haryana mainly due to heat stress and less water availability, but irrigated areas have productivity at par to that of the states of Haryana and Punjab. The quality of wheat is excellent in this region, and this zone is known for the production of durum wheat suitable for making products like pasta, noodle, macaroni, suji, and dalia. Wheat grown in this region has got higher demand in domestic as well as international market and also fetches good price. Good-quality Karnal bunt free wheat is also grown in the Peninsular zone comprising Maharashtra, Karnataka, Goa, and Palni hills of Tamil Nadu. This region is also home to Triticum dicoccum. In Northern hill zones, wheat is cultivated in very small area, mostly under rainfed conditions. The growing period of wheat is variable from one agro-climatic zone to another that affects the vegetative and grain-filling duration leading to differ­ ences in attainable yield. The maximum wheat-growing duration is in Northern Hill Zone, and the minimum is in Peninsular Zone. Wheat is cultivated during winter season from mid-October to April (except in higher hills of north India where the harvesting of wheat is done in the month of May). Sowings of wheat are initiated when the average of day–night temperatures is equal to 23°C. The months of December and January remain to be coldest, followed by com­ paratively warmer and higher temperatures in the months of March to April coinciding to later grown stages of the crop till maturity. Wheat is mainly grown under three pro­ duction conditions, viz., timely sown, irrigated; late sown, irrigated; and timely sown, restricted irrigation. Nearly 89% of the wheat area in the country is irrigated, and most of it lies in north India. The central, peninsular, and hilly areas have comparatively lower coverage of area under irrigation and grow mostly rainfed. In recent years, a new situation of timely sown, restricted/limited irrigation has emerged in some of the areas of the central and peninsular parts where water for irrigation is not available in sufficient quantity, and, thus, the wheat crop is grown with one to two irrigations only (Singh and Kumar, 2021).

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Wheat Science

1.5 Varietal Spectrum The agro-climatic conditions, local preferences and wheat-based food habits, preva­ lence of diseases and pests, wheat-based cropping systems, availability of irrigation, and related input factors have a direct bearing on the types of wheat varieties to be developed for commercial cultivation in the country. The farmers of the country have been provided with a choice of varieties during last 60 years since inception of All India Coordinated Wheat and Barley Improvement Programme in 1965. The Indian wheat improvement programme has significantly contributed to the release of 501 wheat vari­ eties including Triticum aestivum, T. durum, T. dicoccum, and triticale through Central Variety Release Committee (CVRC) or State Variety Release Committee (SVRC) for different agro-climatic zones along with relevant production technology (Table  1.3). This included 422 bread wheat, 68 durum, 07 dicoccum, and 04 triticale varieties. Some varieties released in recent past have contributed significantly to enhance wheat production, and, among them, DBW17, PBW550, HD2967, HD3086, WH1105, K0307, GW 322, GW 366, HI 1544, and MACS 6222 are notable in different areas. The recently released cultivars are presented in Table 1.4, which are becoming popu­ lar among the farmers. Most of the farmers are still growing old varieties having low productivity like Sonalika, Raj 3765, UP 262, WH 147, and HUW 234. In this situa­ tion, farmers have to grow recommended new varieties. A list of improved varieties recommended for different production condition is given in Table 1.4.

1.6 Wheat Production Technology The adoption of recommended production technology is a key component for real­ izing higher yields and reducing the gap between experimental and farmers’ fields. The optimized production technology for different production conditions in India is summarized as follows (Singh et al., 2014; Singh et al., 2016).

1.6.1 Soil Testing It gives information about soil fertility of the particular field so that one can apply fertilizers as per soil requirement/recommendations. It is done usually in October or TABLE 1.3 Released Wheat Varieties in India (1965–2021) Crop Species Bread wheat  (T. aestivum) Durum wheat (T. durum) Dicoccum wheat (T. dicoccum) Triticale Total

CVRC

SVRC

Total

267

155

422

45

23

68

6

1

7

4 322

179

4 501

11

Wheat TABLE 1.4 Wheat Varieties for Diverse Agro-Climatic and Production Conditions Production Condition

Improved Cultivars

Early sown, irrigated Timely sown, irrigated

DBW 327, DBW 332, DBW 187, DBW 303, WH 1270 DBW 222, HD 3226, WB 02, HPBW 01, PBW 723, DBW 88, HD 3086, WH 1105 PBW 771, PBW 752, DBW 173, DBW 90, WH 1124, DBW 71, HD 3059, PBW 590, PBW 757, HI 1621, HD 3271 DBW 296, HUW 838, HI 1628, NIAW 3170, HD 3237, HI 1620, WH 1142, HD 3043, PBW 660, PBW 644, WH 1080 KRL 19, KRL 210, KRL 213 DBW 222, HD 3249, HD 3086, DBW 187, K 1006, HD 2967, NW 5054, DBW 39, RAJ 4120, K 0307 HI 1621, DBW 107, HD 3118, HD 2985, HI 1563, HD 3271 DBW 252, HI 1612, K 1317, HD 3171, HD 3293 KRL 19, KRL 210, KRL 213 GW 513, HI 1636, HI 1544, GW 366, GW 322, HI 8759 (d), HD 4728 (d), HI 8737 (d), HI 8713 (d), MPO 1215 (d) HI 1634, CG 1029, RAJ 4238, MP 3336, MP 1203 DBW 110, HI 1500, MP 3173, MP 3288, DDW 47(d), UAS 466 (d), HI 8627 (d), HI 8823 (d) KRL 19, KRL 210, KRL 213 DBW 168, MACS 6478, UAS 304, MACS 6222, DDW 48 (d), MACS 3949 (d), WHD 948 (d), UAS 428 (d), UAS 415 (d), HW 1098 (dic), MACS 2971 (dic), DDK 1029 (dic), DDK 1025 (dic) HI 1633, HD 3090, AKAW 4627, HD 2932, Raj 4083 NIAW 3170, MP 1358, HI 1605, DBW 93, NIAW1415, PBW 596, UAS 375, UAS 347, MACS 4028 (d), HI8777 (d), UAS 446 (d), NIDW 1149 (d), GW 1346 (d), HI 8802 (d), HI 8805 (d), MACS 4058 (d) HS 562, HPW 349, VL 907, HS 507 HS 490, VL 892 HS 542, HPW 251, VL 829 VL 832

Late sown, irrigated Timely sown, restricted irrigation Sodic soils/others Timely sown, irrigated Late sown, irrigated Timely sown, restricted irrigation Sodic soils/others Timely sown, irrigated Late sown, irrigated Timely sown, restricted irrigation Sodic soils/others Timely sown, irrigated

Late sown, irrigated Timely sown, restricted irrigation

Timely sown, irrigated Late sown, irrigated/rainfed Timely sown, rainfed For high-altitude areas

Abbreviations: (d) – durum wheat; (dic) – dicoccum wheat

after the harvesting process of crops. For soil testing, the samples are taken from all corners and middle of the field, mixed well and from it, 500 g soil sample is taken for testing in nearby soil-testing laboratory.

1.6.2 Field Preparation Good field preparation helps in saving the irrigation water by uniform irrigation and weed control. Pre-sowing irrigation followed by ploughing with disc harrow, tiller, and leveller at field capacity is needed for optimum field conditions. Field preparation is done from October, based on crop production condition by good ploughing, followed by planking for moisture conservation. Field should be well prepared by disc harrow and

12

Wheat Science

cultivator as per the requirement of the soil. Field should be well levelled so the use of laser land leveller is quite beneficial. Three-to-four field preparation operations should be done, followed by levelling. To conserve soil moisture, there should not be deep/ heavy cultivation. If sowing is to be done by zero tillage, there is no need to prepare field.

1.6.3 Seed Rate and Treatment Seed rate is an important factor to get maximum yield levels. The recommended seed rate for early sown irrigated, timely sown irrigated, and timely sown restricted irriga­ tion conditions is 100 kg/ha whereas it is 125 kg/ha for late sown irrigated and timely sown rainfed conditions. Seed treatment gives protection to soil and seed-borne dis­ eases and promotes better germination resulting in healthier plants. It should be done one day before sowing. Raxil @1.0 g/kg seed or Vitavax @ 2.0 g/kg seed or Thiram + Vitavax (1:1) may be used for seed treatment for the control of smut diseases. Seed treatment drum may be used for seed treatment only.

1.6.4 Sowing Time and Method Wheat sowing starts from mid-October to January on the basis of production condi­ tions. Irrigated timely sown crop is sown during November 1–15, whereas irrigated late sown crop is sown during December 5–15. The rainfed crop in some areas, spe­ cially NHZ, is sown during 15–31 October. Crop under early sown irrigated and timely sown restricted irrigation condition is sown from 25th October to 5th November. The suitable temperature required for sowing of wheat is 21–25ºC. Sowing is to be done by drilling seed and fertilizer drill. If there is loose straw in the field use of rotary disc drill, Happy Seeder is recommended. Crop residues control weeds in field, and resi­ due retention helps in conserving moisture and increases soil organic matter. Thus, crop residues should not be burnt as these kill beneficial insects. The depth of sowing should be around 5 ± 2 cm, and row spacing for timely sown should be 20 cm. Under late sown condition, row-to-row spacing should be 18 cm. For rainfed areas, line spac­ ing should be 23 cm depending upon soil moisture condition.

1.6.5 Fertilizer Application All essential nutrients are made available through balanced and integrated nutrient management for a healthy crop with higher productivity. Usually, the application of chemical fertilisers in the form of N:P:K is given, which vary from zone and produc­ tion condition. Deficiency of one element may affect the availability of other element. Other micronutrients may be applied as per requirement and deficiency in the soil on the basis of soil-testing reports. The recommended fertiliser dose (RFD) for timely sown irrigated condition is 150:60:40 NPK/ha in NWPZ/NEPZ and 120:60:40 NPK/ ha in NHZ/CZ/PZ, whereas RFD for late sown irrigated condition is 120:60:40 NPK/ ha in NWPZ/NEPZ and 90:60:40 NPK/ha in CZ/PZ. For irrigated conditions, 1/3rd N and full P and K should be applied at sowing and remaining 2/3rd N should be applied in two equal splits at first and second irrigation processes. The RFD under timely sown restricted irrigation condition is 90:60:40 NPK/ha, and timely sown rainfed condition is 60:30:20 NPK/ha where full dose should be applied at sowing. The seed and fertilizer should not be placed at the same place in the soil else they will

Wheat

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affect the germination adversely and productivity will be less. It is suggested to place fertilizers deeper than seed if sown with seed-cum-fertilizer drill.

1.6.6 Irrigation Management Irrigation can be applied depending upon availability of water and requirement of crop. Generally, pre-sowing irrigation is given in October followed by three to six irrigations as per requirement and the availability of irrigation water. Bunds may be prepared in and around the field, and field should be divided in equal parts so that irri­ gation may be uniform, easy, and quick. In the event of availability of six irrigations, the crop stages for irrigation are crown root initiation (CRI) at 21 days after sowing (DAS), tiller completion at 40–45 DAS, booting/late jointing at 60–65 DAS, head­ ing/flowering at 80–85 DAS, milk stage at 100–105 DAS, and dough stage at 115– 120DAS. CRI and heading are the two most sensitive stages where moisture stress causes maximum damage to this crop. Irrigation scheduling can be managed for five (21, 45, 65, 85, and 105 DAS), four (21, 45, 85, and 105 DAS), and three (21, 65, and 105 DAS) irrigation availability. In zero-tillage sown wheat crop also, irrigation needs to be managed similar to the conventional method of wheat cultivation. In raised bed sown crop, if moisture is less at sowing time, then light irrigation should be applied immediately after sowing for better germination and crop stand. Under restricted irri­ gation condition, one pre-sowing irrigation and another at 45 DAS are recommended whereas rainfed crop may be given pre-sowing irrigation if water is available.

1.6.7 Weed Management The infestation of both grassy and broad leaf weed is one of the major biotic con­ straints in wheat production. The major weeds in wheat crop are Phalaris minor (man­ dusi/kanki), Avena ludoviciana (jangli jai), Chenopodium album (bathua), C. murale (kharbathua,), Cyperus rotundus (montha), Medicago sativa (maina), Melilotus alba (senji), Malwa parviflora (chughra), Convolvulus arvensis (hirankhuri), Cirsium arvense (kandai), Anagallis arvensis (krishnanil), Argemone mexicana (satyanashi), Rumex dentatus (jangali palak), etc. Manual weeding with hand hoe is beneficial for weed control after first irrigation at optimum moisture, but the farmers prefer chemical weed control due to cost and time effectiveness. The use of weed free seed, early sowing, and reduced spacing also helps in weed control. Depending on the weed flora infesting the field, herbicide should be selected. For the control of broad-leaved weeds, the spray of Metsulfuron (Algrip) @ 4 g or Carfentrazone (Affinity) @ 20 g or 2,4 D @ 500 g per hectare dissolved in 250–300 litre of water at 30–35 DAS is recommended, whereas spray of Isoproturon @ 1000 g or Clodinafop (Topik/Point/ Jhatka) @ 60 g or Pinoxaden (Axial 5 EC) @ 40 g or Fenoxaprop (Puma Power) @100 g or Sulfosulfuron @ 25 g per hectare dissolved in 250–300 litre water at 30–35 DAS is recommended for the control of narrow-leaved weeds. For the control of both narrow- and broad-leaved weeds, spray of Isoproturon (Isogaurd 75 WP) @ 500 g or Sulfosulfuron (Leader/SF10/Safal) @ 13 g or Sulfosulfuron + Metsulfuron (Total) @ 16 g or Mesosulfuron+ Iodosulfuron (Atlantis) @ 160 g or Fenoxaprop+ Metribuzin (Accord plus) @ 500–600 ml dissolved in 250–300 litre of water in a hectare at 30–35 DAS is recommended. Pendimethalin (Stomp) @ 1000–1500 ml dissolved in 500 litre of water can also be used in a hectare within 3 days of sowing for weed control.

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1.6.8 Crop-Protection Measures Rusts, foliar blight, Karnal bunt, powdery mildew, smut diseases, and termites are major biotic stresses impacting wheat crops. The use of resistant cultivars is the best option to avoid these biotic stresses. However, chemical control measures are also recommended to control the occurrence of these diseases and pests. The spray of propiconazole (Tilt 25 EC @ 0.1%) or tebuconazole (Folicur 250EC @ 0.1%) or tria­ demefon (Bayleton 25WP @ 0.1%) is recommended to control rust, powdery mildew, and Karnal bunt diseases. Seed treatment with Carboxin (75 WP @ 2.5 g/kg seed) or Carbendazim (50 WP @ 2.5 g/kg seed) or Tebuconazole (2DS @ 1.25 g/kg seed) is recommended to control smut diseases. Seed treatment with chlorpyriphos @ 0.9g a.i./kg seed or thiamethoxam 70WS (Cruiser 70WS) @ 0.7 g a.i./kg seed or Fipronil (Regent 5FS @ 0.3 g a.i./kg seed) is very effective for termite control.

1.6.9 Harvesting, Threshing, and Storage Generally, wheat is manually harvested, but for quick harvesting, combine harvester should be used to avoid losses in grain yield due to shattering and lodging. When the moisture level of grain is 20%, it is the proper time for manual harvesting in which bundles are made and dried for 3–4 days and threshed by thresher. Wheat should be harvested 4–5 days before it is dead ripe to avoid shattering losses. Combine harvest­ ing is convenient due to synchronized maturity of wheat crop, and it is used when the grain moisture is below 14%. Grain quality will be better at the optimum time of harvesting. Before storage, grains should be dried by spreading on tarpaulin plastic sheets in bright sunlight to keep a moisture level below 12%. Bins and silos made of GI sheets are used for storage. Nowadays, aluminium bins, puma bins, silos, and poly­ lined bags are available for storage. Farmers can store wheat grains in their traditional storage as well. To protect from storage insects or pests, it is necessary to fumigate the produce with FDB @ 5 g/tons or aluminium phosphide @ 3 g/ton and keeping room sealed for 24 hours. Storage at high-moisture condition should be avoided to maintain seed/grain viability and minimize storage pest damage.

1.7 Emerging Challenges Wheat improvement programme has significantly contributed in yield enhancement at global and national levels, and the occurrence of Green Revolution in South Asia espe­ cially in India is a landmark success story. Increasing production and productivity in a sustainable basis in economic, social and environmental terms, while considering the diversity of agricultural conditions, is one of the most important challenges that the world faces today (G20 meeting, 2012). The demand by 2050 is predicted to increase by 50% from today’s levels. To meet this demand, global annual yield has to increase by almost 50% from the present level (Giraldo et al., 2019) through increased adoption of modern varieties and improved productivity. Although the global food security has been ensured till date, but there are numerous emerging challenges to sustain future wheat production targets. Climate change and variations (Aryal et al., 2016; Mehar et al., 2016; Mittal and Hariharan, 2018), wide yield gap between the farmer’s field and experimental farms (Ghimire et al., 2012; Pavithra et al., 2017), unavailability of

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improved seeds (Lantican et al., 2016), use of self-saved old seeds (Abeyo et al., 2020), change in biotic and abiotic stress spectrum (Pingali, 1999; Lantican et  al., 2016), cropping pattern shifts (Islam et al., 2020), depleting soil quality due to over extrac­ tion of nutrients, micronutrient deficiencies, declining water tables, salinity, sodicity, etc., are the biggest threats as these impact wheat yield potential and productivity.

1.8 Priorities in Wheat Improvement There is a need of multidisciplinary collaborations for effective planning, implemen­ tation, and evaluation of research priorities. Most priorities in wheat breeding remain the same and for which faster development and the accumulation of knowledge from different fields are needed to provide new strategies and paths to reach these goals. Increasing yield potential has been prioritized as the main objective of wheat breeding over many decades in order to meet the food requirements of an ever-increasing popu­ lation (Borlaug, 2007; Pingali, 2012). Disease resistance is the next most important trait since the first breeding attempts by Knight in 1787 until today in different coun­ tries (Lupton, 1987). The old diseases like rusts are still a potential threat for wheat cultivation, but the most recent diseases such as wheat blast are also posing a con­ cern for wheat cultivation worldwide (Wulff and Dhugga, 2018). Tolerance to abiotic stresses (especially drought, heat, cold, acid soils, and lodging), dual-purpose (forage and grain), improved nutrient use, various quality traits and grain bio-fortification efficiency, and increasing photosynthetic capacity were other traits of importance for wheat improvement. These traits are prioritised within each environmental region and over time. The most important steps for wheat improvement were already reviewed for different traits, that is yield potential (Evenson and Gollin, 2003; Reynolds and Borlaug, 2006), rust resistance (Singh et al., 2006a), drought tolerance (Mwadzingeni et  al., 2016), physiological efficiency (Reynolds et  al., 2011; Rangan et  al., 2016), bio-fortification (Xu et al., 2011; Umar et al., 2019), low gluten content (Green and Jabri, 2003; Spaenij-Dekking et  al., 2005; Catassi et  al., 2013; Rosell et  al., 2014) which are becoming potentially important targets for wheat breeding in recent years. Additionally, the identification of resource use, adaptation and mitigation strategies for targeted environments, bio-risk analysis, development of disease prediction mod­ ules, integrated pest management strategies, crop modelling, tailoring genotypes in cropping system perspective, public and private partnerships, (Hobbs and Morris, 1996; Wheat initiative, 2013; IIWBR, 2015) and strategies for reduced yield gaps including participatory approach (Joshi and Witcombe, 1996; Witcombe et al., 1996; Dixon et al., 2006; Joshi et al., 2017; Abeyo et al., 2020) are key components in achiev­ ing future targets.

1.9 Approaches in Wheat Improvement Wheat is a self-pollinated species, and, therefore, the conventional structure of its breeding programmes includes the use of artificial hybridizations between selected genotypes, something already performed for more than two centuries, and differ­ ent forms of selection within segregating populations (Lupton, 1987; Scheeren et al., 2011). It is recognized that these conventional procedures were, and will continue to

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be, the main approach for the development of wheat cultivars worldwide. However, new tools and techniques are assisting this conventional process, increasing its suc­ cess rate and reducing costs, time, and labour. Improving wheat becomes more dif­ ficult due to needs to “match” quantity and quality, allying yield with grain and flour quality (Shewry, 2009). Also, restricted genetic variability in wheat and its genome size, complexity, and polyploid nature constitute a challenge when applying advanced breeding techniques. Wheat is probably the one among all crop species in which the use of wild and cultivated relatives was extensively exploited as a source of variability for its improve­ ment since long ago, as early as plant breeding itself (Bedo and Láng, 2015). Despite the restricted variability within wheat germplasm, there is an immeasurable richness in variation existing in related species belonging to its secondary and tertiary gene pools (Schneider et al., 2008; Dempewolf et al., 2017; Zhang et al., 2017) that makes gene introgression more prominent (King et al., 2017). Chromosomal translocation of 1RS-1BL between wheat and rye (Secale cereale L.) by E.R. Sears is the most impor­ tant introgression to date in wheat, leading to increased yield potential and resistance/ tolerance to biotic and abiotic stresses (Schlegel and Korzun, 1997; Rabinovich, 1998; Crespo-Herrera et al., 2017). The development of synthetic wheat (Liu et al., 2006; Mujeeb-Kazi et al., 2008) and pre-breeding (Molnár-Láng et al., 2015; Singh et al., 2018; Singh et al., 2021a) for trait improvement are some of the remarkable achieve­ ments in wheat improvement. Mutation induction through chemical or physical mutagens has been widely used in wheat (Parry et al., 2009) for the induction of vari­ ability for various traits including resistance to herbicides (Pozniak and Hucl, 2004), increased amylose content, and starch resistance (Slade et al., 2012). The detection of mutants is very difficult (Parry et al., 2009) due to the polyploid nature of wheat, but tilling methods (Slade et al., 2005; Uauy et al., 2009) and high-resolution melting analysis (Dong et al., 2009) have proven to be efficient for the detection of mutations in different genomes of hexaploid wheat. Mutation breeding led to the development of 265 wheat cultivars in different countries (FAO/IAEA, 2022). The use of molecular markers for QTL mapping and marker-assisted selection has been growing (Buerstmayr et al., 2009; Gupta et al., 2017), and different meta-analyses indicated that AFLP, RFLP, and SSR were the most used markers (Chao et al., 1989; Nagaoka and Ogihara, 1997; Song et  al., 2005; Hospital, 2009; Gupta et  al., 2010) during 1990s to 2000s. Recent revolution using the high-throughput genotyping plat­ forms using DArT (Akbari et al., 2006) and SNP (Cavanagh et al., 2013; Wang et al., 2014a; Winfield et al., 2016) markers, genotyping by sequencing (Poland et al., 2012a; Saintenac et al., 2013), and genome-wide association studies (GWAS) facilitated the generation of 20 to 450 K loci maps in wheat and allowed capture of a larger genetic diversity (Cabrera-Bosquet et  al., 2012; Poland et  al., 2012b; Kollers et  al., 2013; Arruda et al., 2016; Liu et al., 2016a; Guo et al., 2017). The limitation of MAS to aid the selection for a few genes or alleles at a time has been overcome by a recent approach of genomic selection (GS) to handle numerous genes of quantitative nature (Meuwissen et al., 2001) which perform selection and prediction of breeding values based only on genotyping (Jannink et al., 2010) with greater accuracy (Heffner et al., 2009; Poland et al., 2012b; Arruda et al., 2015; Bassi et al., 2016). The International Wheat Genome Sequencing Consortium (IWGSC) facilitated the generation of a reference genome of wheat based on hexaploid wheat cultivar Chinese Spring (IWGSC, 2014; IWGSC, 2018) which has been considered a step-change for more effective use of genomics in

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breeding. The development of transgenic plants (Shewry, 2009; Hilbeck et al., 2015; Lynas, 2012) for various traits of resistance to biotic (Zhao et al., 2006; Janni et al., 2008; Li et al., 2015) and abiotic stresses (Gao et al., 2009), baking quality (Rakszegi et al., 2005), and cisgenic plants (Tester and Langridge, 2010) was an effective tool, but did not get suitable acceptance for large-scale commercial cultivation (Vasil et al., 1992; Vasil, 2007; Wulff and Dhugga, 2018). The most recent and promising innova­ tion of genome or gene editing (Sander and Joung, 2014; Bortesi and Fischer, 2015; Brozynska et al., 2016; King et al., 2017), which accurately targets segments of the genome for modification, by deletion, insertion, or substitution of nucleotides (Sander and Joung, 2014), has proven to be successful (Shan et al., 2013; Upadhyay et al., 2013; Shan et al., 2014; Wang et al., 2014b; Zhang et al., 2016) despite the great complexity of its extensive, redundant, and polyploid genome. The precise gene replacement in gene editing can also mitigate linkage drag making it a potential tool for gene intro­ gression from wild relatives into wheat background (Wang et al., 2018). The development and cultivation of hybrid cultivars are one of the innovative approaches for breaking yield barriers (Singh et al., 2010: Longin et al., 2013) which indicate the future importance in changing climatic conditions (Mühleisen et  al., 2014) due to higher yield stability. Hybrids provide protection against various biotic (Longin et al., 2013; Miedaner et al., 2017; Beukert et al., 2020) and abiotic stresses (Longin et al., 2013; Gomaa et al., 2014) and exhibit improved grain quality, enhanced fertilizer response, better root growth, and high rate of grain filling (Hallauer et al., 1988; Kindred and Gooding, 2005; Xu et al., 2011; Ahmad et  al., 2016). However, several difficulties associated with hybrid development and seed production limited its cultivation in less than 1% of the global area under wheat (Longin et  al., 2012; Whitford et al., 2013; Kempe et al., 2014; Würschum et al., 2018a; Würschum et al., 2018b; Thorwarth et al., 2018; Miedaner and Laidig, 2019). Now research in the devel­ opment and cultivation of hybrids seems to be a priority in wheat breeding due to a huge accumulation of knowledge and new technologies (Zhao et al., 2015; Liu et al., 2016b; Gaynor et al., 2017; Watson et al., 2018; Gupta et al., 2019; Singh et al., 2021b). The speed breeding, based on photoperiod, light, and temperature manipulation (artificially) in growth chambers and glasshouses, is a recent tool to shorten breeding cycle of wheat cultivars (Watson et al., 2018) and expedite phenotyping for various traits (Ghosh et al., 2018; Singh et al., 2020). The use of high-throughput phenotyping also aims to evaluate several traits in a large number of plants over a short period of time (de Souza, 2010; Cabrera-Bosquet et  al., 2012; Araus and Cairns, 2014). This technique comprises several highly optimized and automated steps (Kipp et al., 2014; Fahlgren et  al., 2015) under controlled conditions (Fahlgren et  al., 2015; Richard et  al., 2015) as well as in-field conditions (Comar et  al., 2012; Kipp et  al., 2014; Haghighattalab et  al., 2016; Tattaris et  al., 2016). These recent techniques become effective components for faster cultivar development programmes.

1.10 Conclusion Wheat, being a nutri-rich grain, has a significant role in ensuring food and nutritional security for establishing zero hunger as committed under the Sustainable Development Goals (SDGs). Modern wheat cultivars usually refer to two species, namely, hexa­ ploid bread wheat and tetraploid durum wheat. Wheat is a superb model organism for

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the evolutionary theory of allopolyploid speciation, adaptation, and domestication in plants (Gustafson et al., 2009). During agricultural development, early domesticates were gradually replaced first by landraces and traditional varieties and later by geneti­ cally less diverse modern cultivars. This has resulted in genetic bottlenecks in modern breeding processes of improved germplasm and caused substantial genetic erosion (Tanksley and McCouch, 1997; Nevo, 2004; Fu and Somers, 2009) and thus increased susceptibility and vulnerability to environmental stresses, pests, and diseases (Fu and Somers, 2009; Nevo 2009, 2011). Although the narrow gene pool available for the development of superior varieties is of major concern heightened by increasing global population predictions, breeding programmes had considerable success in produc­ ing higher yielding varieties in the past with the limited available variation. There is growing evidence that wheat yields are plateauing due to the exhaustion of the avail­ able genetic variation compounded by environmental change (Brisson et  al., 2010; Charmet, 2011; Ray et al., 2013). Thus, there is an urgent need to identify new sources of genetic variation that can be used in future genetic improvement to develop supe­ rior wheat varieties for feeding the ever-increasing human population. Though expe­ riencing diversity bottlenecks, wheat has strong adaptability to diverse environments and end uses (Nevo et al., 2002) as it compensates these bottlenecks by capturing part of the genetic diversity of its progenitors and by generating new diversity at a rela­ tively fast pace (Dubcovsky and Dvorak, 2007). Therefore, the best strategy for wheat improvement is to utilize the adaptive genetic resources of the wild progenitors, wild emmer T. dicoccoides, and other wheat relatives for which germplasm collections are essential to conserve biodiversity and efficient utilization for future wheat improve­ ment programmes (Feldman and Sears, 1981; Nevo and Beiles, 1989; Nevo, 2007; Johnson, 2008; Xie and Nevo, 2008; Nevo and Chen, 2010). The current challenges of adversaries of climate change, restricted availability of arable land and water, diversification in cropping pattern, constant evolution of patho­ gens, and quality requirements are major obstacles in sustaining the pace of wheat productivity and production which posed a significant pressure on wheat-breeding programmes to maintain productivity along with improved resistance to biotic and abiotic stresses. These challenges also linked issues of varietal replacement, sustain­ able input utilization, and changing socio-economics of the growing population. It is important to increase the yield levels in a sustainable manner and reduce the yield gaps through the use of improved cultivars, efficient utilization of inputs for better soil health, adoption of recommended production technologies for weed and pest manage­ ment, and improved extension services in participatory mode. Breeding has been responsible for increasing wheat yields and improving many other traits, such as resistance to biotic and abiotic stresses and grain quality. In order to meet its global demand, efforts in the development and implementation of improved strategies must continuously take place in wheat-breeding programs. Classical meth­ ods of wheat breeding, which are largely based on crosses and phenotypic selection, have been the most used plant breeding methods around the globe for more than one century and significantly contributed to develop elite breeding lines and release of the largest number of cultivars (Prohens, 2011). This approach seems to be main strategy for future wheat improvement programmes especially in developing coun­ tries. Plant breeding has experienced innovations and revolutions throughout its exis­ tence, and wheat has been witness to most of these transformations and probably will continue as an ally of the transformations to come. The availability of fast-track

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improved genomic approaches has made it possible to mobilize gene-bank variation to the breeding pipelines (Singh et al., 2021a) and discover a large number of novel genes, which can be easily incorporated into inferior genotypes using marker-aided interventions. The application of next-generation sequencing (NGS) platforms and bioinformatics tools has revolutionized the pre-breeding activities (Singh et al., 2018) and wheat genomics to identify marker–trait associations and direct insertion of a gene of interest through gene editing and phenotypic selection by genomic selection for faster wheat improvement. The combined approaches of conventional methodolo­ gies supported by modern tools and techniques will probably predominate in future breeding programs.

REFERENCES Abeyo B, Badebo A, Gebre D and Listman M. 2020. Achievements in fast-track variety testing, seed multiplication and scaling of rust resistant varieties: lessons from the wheat seed scaling project. Ethiopia. CDMX, Mexico, and Addis Ababa, Ethiopia: The International Maize and Wheat Improvement Center (CIMMYT) and the Ethiopian Institute of Agricultural Research (EIAR). Ahmad E, Kamar A  and Jaiswal JP. 2016. Identifying heterotic combinations for yield and quality traits in bread wheat (Triticum aestivum L.). Electron J Plant Breed 7(2):352–61. Akbari M, Wenzl P, Caig V, Carling J, Xia L, Yang S, Uszynski G, Mohler V, Lehmensiek A, Kuchel H, Hayden MJ, Howes N, Sharp P, Vaughan P, Rathmell B, Huttner E and Kilian A. 2006. Diversity arrays technology (DArT) for high-throughput profil­ ing of the hexaploid wheat genome. Theor Appl Genet. 113:14 09–20. https://doi. org/10.1007/s00122-006-0365-4. Ali A, Hussain M, Hassan S and Nadeem N. 2017. Estimation of total factor productivity growth of major grain crops in Pakistan: 1972–2013. Int Rev Soc Sci 54:237–45. Ali M and Byerlee D. 2002. Productivity growth and resource degradation in Pakistan’s Punjab: a decomposition analysis. Econ Dev Cult Chang 504:839–63. Araus JL and Cairns JE. 2014. Field high-throughput phenotyping: the new crop breed­ ing frontier. Trends Plant Sci 19:52– 61. https://doi.org/10.1016/j.tplants.2013.09.008. Arruda MP, Brown PJ, Brown-Guedira G, Krill AM, Thurber C, Merrill KR, Foresman BJ, Frederic L and Kolb FL. 2016. Genome-wide association mapping of Fusarium head blight resistance in wheat using genotyping-by-sequencing. Plant Genome 9(1) :1–14. https://doi.org/10.3835/plantgenome.2015.04.0028. Arruda MP, Brown PJ, Lipka AE, Krill AM, Thurber C and Kolb FL. 2015. Genomic selec­ tion for predicting Fusarium head blight resistance in a wheat breeding program. The Plant Genome 8(3) :1–12. https://doi.org/10.3835/plantgenome.2015.01.0003. Aryal JP, Sapkota TB, Jat ML, Jat HS, Rai M, Mittal S, Stirling CM and Sutaliya JM. 2016. Conservation agriculture-based wheat production better copes with extreme climate events than conventional tillage-based systems: a case of untimely excess rainfall in Haryana, India. Agric Ecosyst Environ 233:325–35. Avni R, Nave M, Barad O, Baruch K, Twardziok SO, Gundlach H, Hale I, Mascher M, Spannagl M, Wiebe K, Jordan KW, Golan G, Deek J, Ben-Zvi B, Ben-Zvi G, Himmelbach A, MacLachlan RP, Sharpe AG, Fritz A, Ben-David R, Budak H, Fahima T, Korol A, Faris JD, Hernandez A, Mikel MA, Levy AA, Steffenson B, Maccaferri M, Tuberosa R, Cattivelli L, Faccioli P, Ceriotti A, Kashkush K, Pourkheirandish M, Komatsuda T, Eilam T, Sela H, Sharon A, Ohad N, Chamovitz

20

Wheat Science

DA, Mayer KFX, Stein N, Ronen G, Peleg Z, Pozniak CJ, Akhunov ED and Distelfeld A. 2017. Wild emmer genome architecture and diversity elucidate wheat evolution and domestication. Science 357:93–7. Bassi FM, Bentley AR, Charmet G, Ortiz R and Crossa J. 2016. Breeding schemes for the implementation of genomic selection in wheat (Triticum spp.). Plant Sci 242 :23–36 https://doi.org/10.1016/j.plantsci.2015.08.021. Bedo Z and Láng L. 2015. Wheat breeding: current status and bottlenecks. In: Molnar M, Ceoloni C and Doležel J (Eds) Alien introgression in Wheat: cytogenetics, molecu­ lar biology, and genomics, 1st edn. New York: Springer International Publishing, pp. 203–62. Beukert U, Liu G, Thorwarth P, Boeven PHG,  Friedrich C, Longin H,  Zhao Y,  Ganal M,  Serfling A,  Ordon F  and  Reif JC. 2020. The potential of hybrid breeding to enhance leaf rust and stripe rust resistance in wheat. Theor Appl Genet 133:2171–81. Bhushan S. 2016. TFP growth of wheat and paddy in post-green revolution era in India: parametric and non-parametric analysis. Agric Econ Res Rev 291:27–40. Bilgic H, Hakki EE, Pandey A, Khan MK and Akkaya  MS. 2016. Ancient DNA from 8400 year-old Çatalhöyük Wheat: implications for the origin of Neolithic agricul­ ture. PLoS One 11:e01 51974. https://doi.org/10.1371/journal.pone.0151974. Blake NK, Lehfeldt BR, Lavin M and Talbert LE. 1999. Phylogenetic reconstruction based on low copy DNA sequence data in an allopolyploid: The B genome of wheat. Genome 42:351–60. Borlaug NE. 2007. Sixty-two years of fighting hunger: personal recollections. Euphytica 157:287– 97. https://doi.org/10.1007/s10681-007-9480-9. Bortesi L and Fischer R. 2015. The CRISPR/Cas9 system for plant genome editing and beyond. Biotechnol Adv 33:41– 52. https://doi.org/10.1016/j.biotechadv.2014.12.006. Breiman A and Graur D. 1995. Wheat evolution. ISR J Plant Sci 43(2):85–98. Brisson N, Gate P, Gouache D, Charmet G, Oury FX and Huard F. 2010. Why are wheat yields stagnating in Europe? A comprehensive data analysis for France. Field Crops Res 119:201–12. Brozynska M, Furtado A and Henry RJ. 2016. Genomics of crop wild relatives: expand­ ing the gene pool for crop improvement. Plant Biotechnol J 14:10 70–85. https://doi. org/10.1111/pbi.12454. Buerstmayr H, Ban T and Anderson JA. 2009. QTL mapping and marker-assisted selec­ tion for Fusarium head blight resistance in wheat: a review. Plant Breed 128 :1–26. https://doi.org/10.1111/j.1439-0523.2008.01550.x. Byerlee D, Ali M and Siddiq A. 2003. Sustainability of the rice–wheat system in Pakistan’s Punjab: how large is the problem? In: Improving the productivity and sustainability of rice-wheat systems: issues and impacts, vol. 65, pp. 77–95. Cabrera-Bosquet L, Crossa J, von Zitzewitz J, Serret MD and Araus JL. 2012. Highthroughput phenotyping and genomic selection: the Frontiers of crop Breeding con­ verge. J Integr Plant Biol 54:3 12–20. https://doi.org/10.1111/j.1744-7909.2012.01116.x. Catassi C, Bai JC, Bonaz B, Bouma G, Calabrò A, Carroccio A, Castillejo G, Ciacci C, Cristofori F, Dolinsek J, Francavilla R, Elli L, Green P, Holtmeier W, Koehler P, Koletzko S, Meinhold C, Sanders D, Schumann M, Schuppan D, Ullrich R, Vécsei A, Volta U, Zevallos V, Sapone A and Fasano A. 2013. Non-celiac gluten sensitiv­ ity: the new frontier of gluten related disorders. Nutrients 5:3 839–53 https://doi. org/10.3390/nu5103839. Cavanagh CR, Chao S, Wang S, Huang BE,  Stephen S, Kiani S,  Forrest K, Saintenac C, Brown-Guedira GL, Akhunova A, See D, Bai GH, Pumphrey M, Tomar L, Wong D,  Kong S,  Reynolds M, Lopez  M, da Silva,  Bockelman H,  Talbert L,  Anderson

Wheat

21

JA,  Dreisigacker S, Baenziger S,  Carter A,  Korzun V,  Morrell PL,  Dubcovsky J, Morell MK, Sorrells ME, Hayden MJ and Eduard Akhunov E. 2013. Genomewide comparative diversity uncovers multiple targets of selection for improvement in hexaploid wheat landraces and cultivars. Proc Natl Acad Sci 110:8057–62. https:// doi. org/10.1073/pnas.1217133110. Chakraborty M, Mahmud NU, Gupta DR, Tareq FS, Shin HJ and Islam T. 2020. Inhibitory effects of linear lipopeptides from a marine Bacillus subtilis on the wheat blast fun­ gus Magnaporthe oryzae Triticum. Front Microbiol 1 1:665. https://doi.org/10.3389/ fmicb.2020.00665. Chalupska D, Lee HY, Faris JD, Evrard A, Chalhoub B, Haselkorn R and Gornicki P. 2008. Acc homoeo loci and the evolution of wheat genomes. Proc Natl Acad Sci USA 105:9691–96. Chao S, Sharp PJ, Worland AJ, Warham EJ, Koebner RMD and Gale MD. 1989. RFLPbased genetic maps of wheat homoeologous group 7 chromosomes. Theor Appl Genet 78(4):49 5–504. https://doi.org/10.1007/BF00290833. Charmet G. 2011. Wheat domestication: lessons for the future. C R Biol 334:2 12–20. https://doi.org/10.1016/j.crvi.2010.12.013. Comar A, Burger P, de Solan B, Baret F, Daumard F and Hanocq JF. 2012. A semi-automatic system for high throughput phenotyping wheat cultivars in-field conditions: descrip­ tion and first results. Funct Plant Biol 39:914 https://doi.org/10.1071/FP12065. Crespo-Herrera L, Garkava-Gustavsson L and Åhman I. 2017. A systematic review of rye (Secale cereale L.) as a source of resistance to pathogens and pests in wheat (Triticum aestivum L.). Hereditas 154(14) :1–9. https://doi.org/10.1186/s41065-017-0033-5. DAC&FW. 2021. Latest APY state data. Directorate of Economics and Statistics, Department of Agricultural Cooperation & Farmers Welfare, Govt of India. https:// eands.dacnet.nic.in/APY_96_ To_06. htm. Accessed on 12.7.2022. Datt G and Ravallion M. 1998. Farm productivity and rural poverty in India. J Develop Stud 34, 62–85. de Souza N. 2010. High-throughput phenotyping. Nat Methods 7(1): 36. https://doi. org/10.1038/nmeth.f.289. Dempewolf H, Baute G, Anderson J, Kilian B, Smith C and Guarino L. 2017. Past and future use of wild relatives in crop Breeding. Crop Sci. 10 70–82. https://doi. org/10.2135/cropsci2016.10.0885. Dixon J, Nalley L, Kosina P, LaRovere R, Hellin J and Aquino P.  2006. Adoption and economic impact of improved wheat varieties in the developing world. J Agric Sci 144:489–502. Dong C, Vincent K and Sharp P. 2009. Simultaneous mutation detection of three homoeol­ ogous genes in wheat by high resolution melting analysis and mutation surveyor. BMC Plant Biol 9:143 https://doi.org/10.1186/1471-2229-9-143. Dubcovsky J and Dvorak J. 2007. Genome plasticity a key factor in the success of poly­ ploid wheat under domestication. Science 316:18 62–66. https://doi.org/10.1126/ science.1143986. Dvorak J, Deal KR, Luo M-C, You FM, von Borstel K and Dehghani H. 2012. The origin of spelt and free-threshing hexaploid wheat. J Hered 103:426–41. El Baidouri M, Murat F, Veyssiere M, Molinier M, Flores R, Burlot L, Alaux M, Quesneville H, Pont C and Salse J. 2017. Reconciling the evolutionary origin of bread wheat (Triticum aestivum). New Phytol 213:1477– 86. https://doi.org/10.1111/ nph.14113. Evenson RE and Gollin D. 2003. Assessing the impact of the green revolution, 1960 to 2000. Science 300: 758–62 https://doi.org/10.1126/science.1078710.

22

Wheat Science

Evenson RE and Rosegrant MW. 2003. The economic consequences of crop genetic improvement programmes. In Evenson R and Gollin D (Eds) Crop variety improve­ ment and its effect on productivity: the impact of international agricultural research. Wallingford: CABI Publishing. Fahlgren N, Gehan MA and Baxter I. 2015. Lights, camera, action: high-throughput plant phenotyping is ready for a close-up. Curr Opin Plant Biol 24 :93–9. https://doi. org/10.1016/j.pbi.2015.02.006. Fan S and Hazell P. 2001. Returns to public investments in the less favoured areas of India and China. Am J Agri Econ 83(5):1217–22. FAO. 2011. Food and agriculture organiz ation. www.fao.org/statistics/en FAO. 2017. The future of food and agriculture—trends and challenges. Rome: FAO. FAO. 2020. Data: production. Online database Crop Prod Harvest Area. www.fao.org/ faostat/en/#data/QC. Accessed on 26.4.2020. FAO. 2021. World food situation. Cereal Supply and Demand Brief. www.fao.org/world­ food situation/csdb/en/. Accessed on 12.7.2022. FAO/IAEA. 2022. Mutant variety database. https://nucleus.iaea.org/sites/mvd/SitePages/ Home.aspx. Accessed on 7.7.2022. Feldman M. 1995. Wheats. In: Smartt J and Simmonds NW (orgs) Evolution of crop plants. Harlow: Longman Scientific and Technical, pp. 185–92. Feldman M, Lupton FGH and Miller TE. 1995. Wheats. In: Smartt J and Simmonds NW (Eds) Evolution of crop plants, 2nd edn. Harlow: Longman Scientific & Technical, pp. 184–92. Feldman M and Sears ER. 1981. The wild gene resources of wheat. Sci Am 244:102–13. Fischer RA, Byerlee D and Edmeades G. 2014. Crop yields and global food security: will yield increase continue to feed the world? (ACIAR monograph no. 158). Canberra: Australian Centre for International Agricultural Research, p. 634. Fu YB and Somers DJ. 2009. Genome-wide reduction of genetic diversity in wheat breed­ ing. Crop Sci 49:161–8. G20 Meeting. 2012. Agriculture vice-ministers and deputies meeting report. www. mofa. go.jp/policy/economy/g20_summit/2012/pdfs/am_report_e.pdf Gao SQ, Chen M, Xia LQ, Xiu HJ, Xu ZS, Li LC, Zhao CP, Cheng XG and Ma YZ. 2009. A cotton (Gossypium hirsutum) DRE-binding transcription factor gene, GhDREB, confers enhanced tolerance to drought, high salt, and freezing stresses in transgenic wheat. Plant Cell Rep 28:3 01–11. https://doi.org/10.1007/s00299-008-0623-9. Gaynor RC, Gorjanc G, Bentley AR, Ober ES, Howell P, Jackson R, Mackay IJ and Hickey JM. 2017. A two-part strategy for using genomic selection to develop inbred lines. Crop Sci 57(5):2372–86. GCARD. 2012. Breakout session P1.1 National Food Security – The wheat initiative – An international research initiative for wheat improvement context – the problems being addressed. In: Proceedings of the GCARD—Second global conference on agricul­ tural research for development. Uruguay: GCARD. Ghimire S, Mehar M and Mittal S. 2012. Influence of sources of seed on varietal adoption behaviour of wheat farmers in Indo-Gangetic Plains of India. Agric Econ Res Rev 25:399–408. Ghosh S, Watson A, Gonzalez-Navarro OE, Ramirez-Gonzalez RH, Yanes L, MendozaSuárez M, Simmonds J, Wells R, Rayner T, Green P, Hafeez A, Hayta S, Melton RE, Steed A, Sarkar A, Carter J, Perkins L, Lord J, Tester M, Osbourn A, Moscou MJ, Nicholson P, Harwood W, Martin C, Domoney C, Uauy C, Hazard B, Wulff BBH and Hickey LT. 2018. Speed breeding in growth chambers and glasshouses for crop breeding and model plant research. Nat Protoc 13:29 44–63. https://doi.org/10.1038/ s41596-018-0072-z.

Wheat

23

Giraldo P, Benavente E, Manzano-Agugliaro F and Gimenez E. 2019. Worldwide research trends on wheat and barley: a bibliometric comparative analysis. Agronomy 9:352. https://doi.org/10.3390/agronomy9070352. Glemin S, Scornavacca C, Dainat J, Burgarella C, Viader V, Ardisson M, Sarah G, Santoni S, David J and Ranwez V. 2018. Pervasive hybridizations in the history of wheat relatives. bioRxiv, 300848. https://doi.org/10.1101/300848. Gomaa MA, El-Banna MNM and Gadalla A. 2014. Heterosis, combining ability and drought susceptibility index in some crosses of bread wheat (Triticum aestivum L.) under water stress conditions. Middle East J Agric Res 3:338–45. Green PHR and Jabri B. 2003. Coeliac disease. Lancet 362:3 83–91. https://doi.org/10.1016/ S0140-6736(03)14027-5. Guo Z, Chen D, Alqudah AM, Röder MS, Ganal MW and Schnurbusch T. 2017. Genomewide association analyses of 54 traits identified multiple loci for the determination of floret fertility in wheat. New Phytol 214:2 57–70. https://doi.org/10.1111/nph.14342. Gupta PK, Balyan HS and Gahlaut V. 2017. QTL analysis for drought tolerance in wheat: present status and future possibilities. Agronomy 7:5. https://doi.org/10.3390/ agronomy7010005. Gupta PK, Balyan HS, Gahlaut V, Saripalli G,  Pal B,  Basnet BR and Joshi AK. 2019. Hybrid wheat: past, present and future. Theor Appl Genet 132(9):2463–83. https:// doi.org/10.1007/s00122-019-03397-y. Gupta PK, Langridge P and Mir RR. 2010. Marker-assisted wheat breeding: pres­ ent status and future possibilities. Mol Breed 26:1 45–61. https://doi.org/10.1007/ s11032-009-9359-7. Gustafson P, Raskina O, Ma X and Nevo E. 2009. Wheat evolution, domestication, and improvement. In: Carver BF (Ed) Wheat: science and trade. Danvers: Wiley, pp. 5–30. Haghighattalab A, González Pérez L, Mondal S, Singh D, Schinstock D, Rutkoski J, OrtizMonasterio I, Singh RP, Goodin D and Poland J. 2016. Application of unmanned aerial systems for high throughput phenotyping of large wheat breeding nurseries. Plant Methods 12(35) :1–15. https://doi.org/10.1186/s13007-016-0134-6. Hallauer AR, Russell WA and Lamkey KR. 1988. Corn breeding. In: Sprague GF and Dudley JW (Eds) Corn and corn improvement, 3rd edn. Madison, WI: American Society Agronomy, pp. 463–564. Hawkes, JG. 1982. Genetic conservation of recalcitrant species – an overview. In: Withers LA and Williams JT (Eds) Crop genetic resources – The conservation of difficult material (Proc. Int. Workshop). Reading: University of Reading, pp. 83–92. Hawkesford MJ, Araus J-L, Park R, Calderini D, Miralles D, Shen T and Zhang JP. 2013. Prospects of doubling global wheat yields. Food Energy Secur 2(1): 34–48. https:// doi.org/10.1002/fes3.15. Heffner EL, Sorrells ME and Jannink J-L. 2009. Genomic selection for crop improvement. Crop Sci 49(1): 12. https://doi.org/10.2135/cropsci2008.08.0512. Heun M, Schäfer-Pregl R, Klawan D, Castagna R, Accerbi M, Borghi B and  Salamini F. 1997. Site of einkorn wheat domestication identified by DNA fingerprinting. Science. 278(5341):1 312–4. https://doi.org/10.1126/science.278.5341.1312. Hilbeck A, Binimelis R, Defarge N, Steinbrecher R, Székács A, Wickson F, Antoniou M, Bereano PL, Clark EA, Hansen M, Novotny E, Heinemann J, Meyer H, Shiva V and Wynne B. 2015. No scientific consensus on GMO safety. Environ Sci Eur 27(4) :1–6. https://doi.org/10.1186/s12302-014-0034-1. Hobbs P and Morris M. 1996. Meeting South Asia’s future food requirements from ricewheat cropping systems: priority issues facing researchers in the post-green revolu­ tion era (NRG Paper 96–01), Mexico, DF: CIMMYT, Mexico.

24

Wheat Science

Hospital F. 2009. Challenges for effective marker-assisted selection in plants. Genetica 136:3 03–10. https://doi.org/10.1007/s10709-008-9307-1. Huang S, Sirikhachornkit A, Su X, Faris J, Gill B, Haselkorn R and Gornicki P. 2002. Genes encoding plastid acetyl-CoA carboxylase and 3-phosphoglycerate kinase of the Triticum/Aegilops complex and the evolutionary history of polyploid wheat. Proc Nat Acad Sci 99:8133–8. Hughes N, Lawson K and Valle H. 2017. Farm performance and climate: climate-adjusted produc­ tivity for broad-acre cropping farms (ABARES Research Report). Canberra: ABARES. IIWBR. 2015. Vision-2050. Karnal: Indian Institute of Wheat & Barley Research, p. 34. International Wheat Genome Sequencing Consortium. 2014. A chromosome-based draft sequence of the hexaploid bread wheat (Triticum aestivum) genome. Science, 345(6194):12 51788. https://doi.org/10.1126/science. International Wheat Genome Sequencing Consortium. 2018. Shifting the limits in wheat research and breeding using a fully annotated reference genome. Science, 361(6403): 7191 https://doi.org/10.1126/science.aar. Islam MT, Gupta DR, Hossain A, Roy KK,  He X, Kabir MR, Singh PK, Khan MAR, Rahman M  and Wang  GL. 2020. Wheat blast: A  new threat to food security. Phytopathol Res 2(28): 1–13. https://doi.org/10.1186/s42483-020-00067-6. Janni M, Sella L, Favaron F, Blechl AE, Lorenzo GD and D’Ovidio R. 2008. The expres­ sion of a bean PGIP in transgenic wheat confers increased resistance to the fungal pathogen Bipolaris sorokiniana. Mol Plant-Microbe Interact 21:1 71–77. https://doi. org/10.1094/MPMI-21-2-0171. Jannink J-L, Lorenz AJ and Iwata H. 2010. Genomic selection in plant breeding: From the­ ory to practice. Brief Funct Genomics 9:1 66–77. https://doi.org/10.1093/bfgp/elq001. Johnson RC. 2008. Gene banks pay big dividends to agriculture, the environment, and human welfare. PLoS Biol 6(6):e148. https://doi.org/10.1371/journal.pbio.0060148. Joshi A and Witcombe JR. 1996. Farmer participatory crop improvement. II. Participatory varietal selection: a case study in India. Exp Agric 32:461–77. Joshi KD, Rehman AU, Ullah G, Nazir MF, Zahara M, Akhtar J, Khan M, Baloch A, Khokhar J, Ellahi E, Khan A, Suleman M and Imtiaz M. 2017. Acceptance and competitiveness of new improved wheat varieties by smallholder farmers. J Crop Improve 31(4):608–27. https://doi.org/10.1080/15427528.2017.1325808. Karim M and Talukder RK. 2008. Analysis of total factor productivity of wheat in Bangladesh. Bangladesh J Agric Econ 31:1–17. Kempe K, Rubtsova M and Gils M. 2014. Split-gene system for hybrid wheat seed produc­ tion. Proc Natl Acad Sci 111:909 7–102. https://doi.org/10.1073/pnas.1402836111. Kihara H. 1944. Discovery of the DD-analyser, one of the ancestors of vulgare wheat. Agric Hortic 19:889–90. Kindred DR and Gooding MJ. 2005. Heterosis for yield and its physiological determinants in wheat. Euphytica 142:149–59. King J, Grewal S, Yang C, Hubbart S, Scholefield D, Ashling S, Edwards KJ, Allen AM, Burridge A, Bloor C, Davassi A, da Silva GJ, Chalmers K and King IP. 2017. A step change in the transfer of interspecific variation into wheat from Amblyopyrum muti­ cum. Plant Biotechnol J 15:217– 26. https://doi.org/10.1111/pbi.12606. Kipp S, Mistele B, Baresel P and Schmidhalter U. 2014. High-throughput phenotyping early plant vigour of winter wheat. Eur J Agron 52:2 71–78. https://doi.org/10.1016/j. eja.2013.08.009. Kollers S, Rodemann B, Ling J, Korzun V, Ebmeyer E, Argillier O, Hinze M, Plieske J, Kulosa D, Ganal MW and Röder MS. 2013. Whole genome association mapping of Fusarium head blight resistance in European winter Wheat (Triticum aestivum L.). PLoS One 8:e57500. https://doi.org/10.1371/journal.pone.

Wheat

25

Kumar P, Kumar A and Mittal S. 2004. Total factor productivity of crop sector in the IndoGangetic Plain of India: sustainability issues revisited. Ind Econ Rev 39(1):169–201. Kumar P and Mittal S. 2006. Agricultural productivity trends in India: sustainability issues. Agric Econ Res Rev 50:71–88. Kumar P, Mittal S and Hossain M. 2008. Agricultural growth accounting and total factor productivity in South Asia: a review and policy implications. Agric Econ Res Rev 21:145–72. Lantican MA, Braun HJ, Payne TS, Singh RP, Sonder K, Baum M, van Ginkel M and Erenstein O. 2016. Impacts of international wheat improvement research, 1994– 2014. Mexico: CIMMYT. Lev-Yadun S, Gopher A and Abbo S. 2000. The cradle of agriculture. Science 288:1 602– 3. https://doi.org/10.1126/science.288.5471.1602. Li X, Shin S, Heinen S, Dill-Macky R, Berthiller F, Nersesian N, Clemente T, McCormick S and Muehlbauer GJ. 2015. Transgenic wheat expressing a barley UDP­ glucosyltransferase detoxifies deoxy-nivalenol and provides high levels of resistance to Fusarium graminearum. Mol Plant-Microbe Interact 28:1237– 46. https://doi. org/10.1094/MPMI-03-15-0062-R. Liu B, Asseng S, Liu L, Tang L, Cao W and Zhu Y. 2016a. Testing the responses of four wheat crop models to heat stress at anthesis and grain filling. Glob Chang Biol 22:1890–903. https://doi.org/10.1111/gcb.13212. Liu G, Zhao Y, Gowda M, Longin CFH, Reif JC and Mette MF. 2016b. Predicting hybrid performances for quality traits through genomic-assisted approaches in central European wheat. PLoS One 11: e0158635. https://doi.org/10.1371/journal.pone. Liu S, Zhou R, Dong Y, Li P and Jia J. 2006. Development, utilization of introgression lines using a synthetic wheat as donor. Theor Appl Genet 112:1360– 73. https://doi. org/10.1007/s00122-006-0238-x. Longin CFH, Gowda M, Mühleisen J, Ebmeyer E, Kazman E, Schachschneider R, Schacht J, Kirchhoff M,  Zhao Y  and  Reif JC. 2013. Hybrid wheat: quantitative genetic parameters and consequences for the design of breeding programs. Theor Appl Genet 126:2791– 801. https://doi.org/10.1007/s00122-013-2172-z. Longin CFH, Mühleisen J, Maurer HP, Zhang H, Gowda M and Reif JC. 2012. Hybrid breeding in autogamous cereals. Theor Appl Genet 125:1087– 96. https://doi. org/10.1007/s00122-012-1967-7. Lupton FGH. 1987. Wheat breeding. Dordrecht: Springer. Lynas M. 2012. Rothamsted’s aphid-resistant wheat – a turning point for GMOs? Agric Food Secur 1(17) :1–3. https://doi.org/10.1186/2048-7010-1-17. Marcussen T, Sandve SR, Heier L, Spannagl M, Pfeifer M, IWGSC, Jakobsen KS, Wulff BBH, Steuernagel B, Mayer KFX and  Olsen OA. 2014. Ancient hybridizations among the ancestral genomes of bread wheat. Science 345(6194):1250092. https:// doi.org/10.1126/science.1250092. McFadden ES and Sears ER. 1946. The origin of Triticum spelta and its free-threshing hexaploid relatives. J Hered 37:1 07–16. https://doi.org/10.1093/oxfordjournals. jhered.a105590. Mehar M, Mittal S and Prasad N. 2016. Farmers coping strategies for climate shock: is it differentiated by gender? J Rural Stud 44:1 23–31. https://doi.org/10.1016/j. jrurstud.2016.01.001. Meuwissen THE, Hayes BJ and Goddard ME. 2001. Prediction of total genetic value using genome-wide dense marker maps. Genetics 157:1819–29. Miedaner T and Laidig F. 2019. Hybrid breeding in rye (Secale cereal L.). In: Al-Khayri JM, et al (Eds) Advances in plant breeding strategies, vol. 5. Cereals and legumes. Cham: Springer, pp. 1–31.

26

Wheat Science

Miedaner T, Schulthess AW, Gowda M, Rief JC and Longin CFH. 2017. High accuracy of predicting hybrid performance of Fusarium head blight resistance by midparent values in wheat. Theor Appl Genet 130:4 61–70. https://doi.org/10.1007/ s00122-016-2826-8. Mittal S. 2022. Wheat and barley production trends and research priorities: a global per­ spective. In: Kashyap PL, Gupta V, Gupta OP, Sendhil R, Gopalareddy K, Jasrotia P and Singh GP (Eds) New horizons in wheat and barley research – global trends, breeding and quality enhancement. Singapore: Springer Nature, pp. 3–18. https:// doi.org/10.1007/978-981-16-4449-8. Mittal S and Hariharan VK. 2018. Mobile based climate services impact on farmers’ risk management ability in India. Clim Risk Manag 22: 42–51. https://doi.org/10.1016/j. crm.2018.08.003. Mittal S and Kumar P. 2000. Literacy, technology adoption, factor demand and productiv­ ity: an econometric analysis. Indian J Agric Econ 55(3):490–9. Mittal S and Lal RC. 2001. Productivity and sources of growth for wheat in India. Agric Econ Res Rev 14(2):109–20. Molnár-Láng M, Ceoloni C and Doležel J. 2015. Alien introgression in wheat: cytogenet­ ics, molecular biology, and genomics, 1st edn. New York: Springer International Publishing. Mühleisen J, Piepho HP and Maurer HP. 2014. Yield stability of hybrids versus lines in wheat, barley, and triticale. Theor Appl Genet 127:309–16. Mujeeb-Kazi A, Gul A, Farooq M, Rizwan S and Ahmad I. 2008. Rebirth of synthetic hexaploids with global implications for wheat improvement. Aust J Agric Res 59(5):3 91–95. https://doi.org/10.1071/AR07226. Mwadzingeni L, Shimelis H, Dube E, Laing MD and Tsilo TJ. 2016. Breeding wheat for drought tolerance: progress and technologies. J Integr Agric 15:9 35–43. https://doi. org/10.1016/S2095-3119(15)61102-9. Nagaoka T and Ogihara Y. 1997. Applicability of inter-simple sequence repeat polymor­ phisms in wheat for use as DNA markers in comparison to RFLP and RAPD mark­ ers. Theor Appl Genet 94:59 7–602. https://doi.org/10.1007/s001220050456. Nevo E. 2004. Genomic diversity in nature and domestication. In: Henry R (Ed) Diversity and evolution of plants. Genotypic and phenotypic variation in higher plants. Wallingford: CABI Publishing CAB International, pp. 287–315. Nevo E. 2007. Evolution of wild wheat and barley and crop improvement: studies at the Institute of Evolution. ISR J Plant Sci 55:251–63. Nevo E. 2009. Ecological genomics of natural plant populations: The Israeli perspective. In Plant Genomics. Berlin: Springer, pp. 321–44. Nevo E. 2011. Triticum. In Wild crop relatives: Genomic and breeding resources. Berlin: Springer, pp. 407–56. Nevo E and Beiles A. 1989. Genetic diversity of wild emmer wheat in Israel and Turkey. Theor Appl Genet 77:421–55. Nevo E and Chen G. 2010. Drought and salt tolerances in wild relatives for wheat and barley improvement. Plant Cell Environ 33:670–85. https://doi.org/10.1111/j.1365­ 3040.2009.02107.x. Nevo E, Korol AB, Beiles A and Fahima T. 2002. Evolution of wild emmer and wheat improvement: Population genetics, genetic resources and genome organization of wheat’s progenitor, Triticum dicoccoides. Berlin: Springer, p. 64. OECD-FAO. 2020. Agricultural outlook 2020–2029. Rome: FAO . https://doi.org/10.1787/ 112c23b-en.

Wheat

27

Parry MAJ, Madgwick PJ, Bayon C, Tearall K, Hernandez-Lopez A, Baudo M, Rakszegi M, Hamada W, Al-Yassin A, Ouabbou H, Labhilili M and Phillips AL. 2009. Mutation discovery for crop improvement. J Exp Bot 60:28 17–25. https://doi. org/10.1093/jxb/erp189. Pavithra S, Mittal S, Bhat SA, Birthal PS, Shah SA and Hariharan VK. 2017. Spatial and temporal diversity in adoption of modern wheat varieties in India. Agric Econ Res Rev 30(1):57–72. Peng Z, Li X, Yang Z and Liao M. 2011. A new reduced height gene found in the tetraploid semi-dwarf wheat landrace Aiganfanmai. Genet Mol Res 10:2349–57. Percival J. 1921. The wheat plant – a monograph. London: Duckworth and Co., p. 154. Petersen G, Seberg O, Yde M and Berthelsen K. 2006. Phylogenetic relationships of Triticum and Aegilops and evidence for the origin of the A, B, and D genomes of common wheat (Triticum aestivum). Mol Phylogenet Evol 39: 70–82. https://doi. org/10.1016/j.ympev.2006.01.023. Pingali PL. 1999. CIMMYT 1998–99: world wheat facts and trends. Global wheat research in a changing world: challenges and achievements. Mexico: CIMMYT. Pingali PL. 2012. Green revolution: impacts, limits, and the path ahead. Proc Natl Acad Sci 109:12 302–8. https://doi.org/10.1073/pnas.0912953109. Poland JA, Brown PJ, Sorrells ME and Jannink J-L. 2012a. Development of high-den­ sity genetic maps for barley and wheat using a novel two-enzyme genotyping­ by-sequencing approach. PLoS One 7:e 32253. https://doi.org/10.1371/journal. pone.0032253. Poland JA, Endelman J, Dawson J, Rutkoski J, Wu S, Manes Y, Dreisigacker S, Crossa J, Sánchez-Villeda H, Sorrells ME and Jannink J-L. 2012b. Genomic selection in wheat breeding using genotyping-by-sequencing. Plant Genome J 5:1 03–13. https:// doi.org/10.3835/plantgenome2012.06.0006. Pont C, Leroy T, Seidel M, Tondelli A, Duchemin W, Armisen D, Lang D, Bustos-Korts D, Goué N, Balfourier F, Molnar-Lang M, Lage J, Kilian B, Ozkan H, Waite D, Dyer S, Letellier T, Alaux M, Russell J and Salse J. 2020. Tracing the ancestry of modern bread wheats. Nat. Genet 51:1–7. Pont C and Salse J. 2017. Wheat paleohistory created asymmetrical genomic evolution. Curr Opin Plant Biol 36: 29–37. https://doi.org/10.1016/j.pbi.2017.01.001. Poudel P and Poudel MR. 2020. Heat stress effects and tolerance in wheat: a review. J Biol Today World 9:217. https://doi.org/10.35248/2322-3308.20.09.217. Pozniak CJ and Hucl PJ. 2004. Genetic analysis of Imidazolinone resistance in muta­ tion-derived lines of common wheat. Crop Sci 44: 23. https://doi.org/10.2135/ cropsci2004.2300. Prohens J. 2011. Plant breeding: a success story to be continued thanks to the advances in genomics. Front Plant Sci 2:51. Rabinovich SV. 1998. Importance of wheat-rye translocations for breeding modern cultivar of Triticum aestivum L. Euphytica 100:3 23–40. https://doi.org/10.1023/ A:1018361819215. Rajaram S. 2012. Strategy for increasing wheat productivity. In Proceedings of the Regional Consultation on Improving Wheat Productivity in Asia, Bangkok, Thailand; 26–27 April, 2012. 224 p. Rakszegi M, Békés F, Láng L, Tamás L, Shewry PR and Bedo Z. 2005. Technological quality of transgenic wheat expressing an increased amount of a HMW glutenin subunit. J Cereal Sci 42: 15–23. https://doi.org/10.1016/j.jcs.2005.02.006. Rangan P, Furtado A and Henry RJ. 2016. New evidence for grain specific C4 photosyn­ thesis in wheat. Sci Rep 6: 31721. https://doi.org/10.1038/srep31721.

28

Wheat Science

Ray DK, Mueller ND, West PC and Foley JA. 2013. Yield trends are insufficient to double global crop production by 2050. PLoS ONE 8:e66428. Renkow M and Byerlee D. 2010. The impacts of CGIAR research: A  review of recent evidence. Food Policy 35:391–402. Reynolds M, Bonnett D, Chapman SC, Furbank RT, Mane’s Y, Mather DE and Parry MAJ. 2011. Raising yield potential of wheat. Overview of a consortium approach and breeding strategies. J Exp Bot 62:4 39–52. https://doi.org/10.1093/jxb/erq311. Reynolds MP and Borlaug NE. 2006. Impacts of breeding on international collab­ orative wheat improvement. J Agric Sci 144(1) :3–17. https://doi.org/10.1017/ S0021859606005867. Richard C, Hickey LT, Fletcher S, Jennings R, Chenu K and Christopher JT. 2015. Highthroughput phenotyping of seminal root traits in wheat. Plant Methods 11:13. https:// doi.org/10.1186/s13007-015-0055-9. Riehl S, Zeidi M and Conard NJ. 2013. Emergence of agriculture in the foothills of the Zagros Mountains of Iran. Science 341:6 5–7. https://doi.org/10.1126/science. 1236743. Rosell CM, Barro F, Sousa C and Mena MC. 2014. Cereals for developing gluten-free products and analytical tools for gluten detection. J Cereal Sci 59:3 54–64. https:// doi.org/10.1016/j.jcs.2013.10.001. Saintenac C, Jiang D, Wang S and Akhunov E. 2013. Sequence-based mapping of the Polyploid Wheat genome. G3: Genes Genom Genet 3:11 05–14. https://doi. org/10.1534/g3.113.005819. Salamini F, Özkan H, Brandolini A, Schäfer-Pregl R and Martin W. 2002. Genetics and geography of wild cereal domestication in the near east. Nat Rev Genet 3:4 29–41. https://doi.org/10.1038/nrg817. Salse J, Chagué V, Bolot S, Magdelenat G, Huneau C, Pont C, Belcram H, Couloux A, Gardais S, Evrard A, Segurens B, Charles M, Ravel C, Samain S, Charmet G, Boudet N and Chalhoub B. 2008. New insights into the origin of the B genome of hexaploid wheat: evolutionary relationships at the SPA genomic region with the S genome of the diploid relative Aegilops speltoides. BMC Genom 9:555. https://doi. org/10.1186/1471-2164-9-555. Sander JD and Joung JK. 2014. CRISPR-Cas systems for editing, regulating and targeting genomes. Nat Biotechnol 32:3 47–55. https://doi.org/10.1038/nbt.2842. Scheeren PL, Caierão E, Silva MS and Bonow S. 2011. Melhoramento no Brasil de trigo. In: Trigo no Brasil: Embrapa, p. 488. Schlegel R and Korzun V. 1997. About the origin of 1RS.1BL wheat-rye chromo­ some translocations from Germany. Plant Breed 116:5 37–40. https://doi. org/10.1111/j.1439-0523.1997.tb02186.x. Schneider A, Molnár I and Molnár-Láng M. 2008. Utilisation of Aegilops (goatgrass) spe­ cies to widen the genetic diversity of cultivated wheat. Euphytica 163 :1–19. https:// doi.org/10.1007/s10681-007-9624-y. Sears ER. 1952. Homoeologous chromosomes in Triticum aestivum. Genetics 37:624. Shan Q, Wang Y, Li J and Gao C. 2014. Genome editing in rice and wheat using the CRISPR/ CAS system. Nat Protoc 9:239 5–410. https://doi.org/10.1038/nprot.2014.157. Shan Q, Wang Y, Li J, Zhang Y, Chen K, Liang Z, Zhang K, Liu J, Xi JJ, Qiu JL and Caixia Gao C. 2013. Targeted genome modification of crop plants using a CRISPR-Cas system. Nat Biotechnol 31(8):6 86–88. https://doi.org/10.1038/nbt.2650. Shewry PR. 2009. Wheat. J Exp Bot 60:15 37–53. https://doi.org/10.1093/jxb/erp058. Shewry PR and Hey SJ. 2015. The contribution of wheat to human diet and health. Food Energy Secur 4(3):178–202.

Wheat

29

Shiferaw B, Smale M, Braun HJ, Duveiller E, Reynolds M and Muricho G. 2013. Crops that feed the world 10. Past successes and future challenges to the role played by wheat in global food security. Food Secur 5(3):29 1–317. https://doi.org/10.1007/ s12571-013-0263-y. Singh G, Tyagi BS, Gupta A, Kumar V, Tiwari V, Chatrath R, Tiwari R, Singh SK, Saharan MS, Sharma RK, Gupta RK and Sharma I. 2016. Wheat: A guide on special features of varieties for different production conditions in India (India Research Bulletin no. 36). Karnal: Indian Institute of Wheat & Barley Research, p. 68. Singh RP, Hodson DP, Jin Y, Huerta-Espino J, Kinyua MG, Wanyera R, Njau P and Ward RW. 2006a. Current status, likely migration and strategies to mitigate the threat to wheat production from race Ug99 (TTKS) of stem rust pathogen. CAB Rev Perspect Agric Vet Sci Nutr Nat Resour 1(54): 1–13. https://doi.org/10.1079/ PAVSNNR20061054. Singh RP, Kumar A, Gupta RK, Sharma RK, Saharan MS, Chokkar RS, Chandra S, Singh SK, Chand R  & Sharma I. 2014. Bharat mein gehoon ki unnat kheti (Extension Bulletin no. 48). Karnal: Directorate of Wheat Research, p. 44. Singh S, Jighly A, Sehgal D, Burgueño J, Joukhadar R, Singh SK, Sharma A, Vikram P, Sansaloni CP, Govindan V, Bhavani S, Randhawa M, Solis-Moya E, Singh S, Pardo N, Arif MAR, Laghari KA, Basandrai D, Shokat S, Chaudhary HK, Saeed NA, Basandrai AK, Ledesma-Ramírez L, Sohu VS, Imtiaz M, Sial MA, Wenzl P, Singh GP and Bains NS. 2021a. Direct introgression of untapped diversity into elite wheat lines. Nat Food 2:819–27. Singh S, Vikram P, Sehgal D, Burgueño J, Sharma A, Singh SK, Sansaloni CP, Joynson R, Brabbs T, Ortiz C, Solis-Moya E, Govindan V, Gupta N, Sidhu HS, Basandrai AK, Basandrai D, Ledesma-Ramires L, Suaste-Franco MP, Fuentes-Dávila G, Moreno JI, Sonder K, Singh VK, Singh S, Shokat S, Arif MAR, Laghari KA, Srivastava P, Bhavani S, Kumar S, Pal D, Jaiswal JP, Kumar U, Chaudhary HK, Crossa J, Payne TS, Imtiaz M, Sohu VS, Singh GP, Bains NS, Hall A and Pixley KV. 2018. Harnessing genetic potential of wheat germplasm banks through impact-oriented­ pre-breeding for future food and nutritional security. Sci Rep 8:12527. https://doi. org/10.1038/s41598-018-30667-4. Singh SK, Chatrath R and Mishra B. 2010. Perspective of hybrid wheat research: a review. Ind J Agric Sci 80(12):1013–27. Singh SK, Dubey S and Desai SA. 2021b. Hybrid wheat: prospects and future perspec­ tives. In Bishnoi SK, Khan H, Singh SK and Singh GP (Eds) Breeding frontiers in wheat. Jodhpur: Agrobios, pp. 331–65. Singh SK and Kumar S. 2021. Advances in wheat and barley production technologies. In: Yadav AS, Kumar N, Arora S, Srivastava DS and Pant H (Eds) Advances in crop production and climate change. New Delhi: New India Publishing Agency, pp. 27–59. Singh SK, Kumar S, Kashyap PL, Sendhil R and Gupta OP. 2022. Wheat. In: Ghosh PK, Das A, Saxena R, Kar G and Vijay D (Eds) Trajectory of 75 years of Indian agricul­ ture after independence. Singapore: Springer Nature Pte Ltd. Singh SK, Kundu S, Kumar D, Srinivasan K, Mohan D and Nagarajan S. 2006b. Wheat. In Dhillon BS, Saxena S, Agrawal PK and Tyagi RK (Eds) Plant genetic resources: Foodgrain crops. New Delhi: Narosa Publishing House, pp. 58–89. Singh SK, Singh S and Singh GP. 2020. Speed breeding for development of new crop vari­ eties. In NAHEP-CAAST Training manual on pre-breeding and molecular breed­ ing approach – Two important pillars for the vegetable and crop improvement, Feb 17–March 1, New Delhi: NIPB, pp. 20–5.

30

Wheat Science

Slade AJ, Fuerstenberg SI, Loeffler D, Steine MN and Facciotti D. 2005. A reverse genetic, nontransgenic approach to wheat crop improvement by TILLING. Nat Biotechnol 23: 75–81. https://doi.org/10.1038/nbt1043. Slade AJ, McGuire C, Loeffler D, Mullenberg J, Skinner W, Fazio G, Holm A, Brandt KM, Steine MN, Goodstal JF and Knauf VC. 2012. Development of high amylose wheat through TILLING. BMC Plant Biol 12: 69. https://doi.org/10.1186/1471-2229-12-69. Song QJ, Shi JR, Singh S, Fickus EW, Costa JM, Lewis J, Gill BS, Ward R and Cregan PB. 2005. Development and mapping of microsatellite (SSR) markers in wheat. Theor Appl Genet 110:5 50–60. https://doi.org/10.1007/s00122-004-1871-x. Spaenij-Dekking L, Kooy-Winkelaar Y, van Veelen P, Drijfhout JW, Jonker H, Soest LV, Smulders MJM, Bosch D, Gilissen LJWJ and Koning F. 2005. Natural vari­ ation in toxicity of Wheat: potential for selection of nontoxic varieties for celiac disease patients. Gastroenterology 129:797–806. https://doi.org/10.1053/j.gastro. 2005.06.017. Statista, 2022. www.statista.com/statistics/263977/world-grain-production-by-type/2021–22. Accessed on 28.6.2022. Tanksley SD and McCouch SR. 1997. Seed banks and molecular maps: unlocking genetic potential from the wild. Science 277:1063–66. Tattaris M, Reynolds MP and Chapman SC. 2016. A direct comparison of remote sens­ ing approaches for high-throughput phenotyping in plant Breeding. Front Plant Sci 7:1–9. https://doi.org/10.3389/fpls. 2016.01131. Tester M and Langridge P. 2010. Breeding technologies to increase crop production in a changing world. Science 327: 818–22 https://doi.org/10.1126/science.1183700. Thorwarth P, Piepho HP, Zhao Y, Ebmeyer E, Schacht J, Schachschneider R, Kazman E, Reif JC, Würschum T, Friedrich C and Longin H. 2018. Higher gain yield and higher grain protein deviation underline the potential of hybrid wheat for a sustainable agriculture. Plant Breed 137:326–37. Uauy C, Paraiso F, Colasuonno P, Tran RK, Tsai H, Berardi S, Comai L and Dubcovsky J. 2009. A modified TILLING approach to detect induced mutations in tetraploid and hexaploid wheat. BMC Plant Biol 9:115. https://doi.org/10.1186/1471-2229-9-115. Umar M, Nawaz R, Sher A, Ali A, Hussain R and Khalid MW. 2019. Current status and future perspectives of biofortification in wheat. Asian J Res Crop Sci 4(4) :1–14. https://doi.org/10.9734/ajrcs/2019/v4i430079. Upadhyay SK, Kumar J, Alok A  and Tuli R. 2013. RNA-guided genome editing for target gene mutations in Wheat. G3: Genes Genom Genet 3:2 233–8. https://doi. org/10.1534/g3.113.008847. USDA. 2022. www.worldagriculturalproduction.com/crops/wheat.aspx. Accessed on 28.6.2022 van Slageren MW. 1994. Wild wheats: a monograph of Aegilops L and Amblypyrum (Jaub, and Spach) Eig (Poaceae). Wageningen: Wageningen Agricultural University Papers 1994. Vasil IK. 2007. Molecular genetic improvement of cereals: transgenic wheat (Triticum aes­ tivum L.). Plant Cell Rep 26:1 133–54 https://doi.org/10.1007/s00299-007-0338-3. Vasil V, Castillo AM, Fromm ME and Vasil IK. 1992. Herbicide resistant fertile transgenic Wheat plants obtained by micro-projectile bombardment of regenerable embryo­ genic callus. Nat Biotechnol 10:6 67–74. https://doi.org/10.1038/nbt0692-667. Wang J, Luo MC, Chen Z, You FM, Wei Y, Zheng Y and Dvorak J. 2013. Aegilops taus­ chii single nucleotide polymorphisms shed light on the origins of wheat D-genome genetic diversity and pinpoint the geographic origin of hexaploid wheat. New Phytol 198:925–37.

Wheat

31

Wang S, Wong D, Forrest K, Allen A, Chao S, Huang BE, Maccaferri M, Salvi S, Milner SG, Cattivelli L, Mastrangelo AM, Whan A, Stephen S, Barker G, Wieseke R, Plieske J, IWGSC, Lillemo M, MatherD, Appels R, Dolferus R, Brown-Guedira G, Korol A, Akhunova AR, Feuillet C, Salse J, Morgante M, Pozniak C, Luo MC, Dvorak J, Morell M, Dubcovsky J, Ganal M, Tuberosa R, Lawley C, Mikoulitch I, Cavanagh C, Edwards KJ, Hayden M and Akhunov E. 2014a. Characterization of polyploid wheat genomic diversity using a high-density 90,000 single nucleotide polymorphism array. Plant Biotechnol J 12:787–96. https://doi.org/10.1111/pbi. 12183. Wang Y, Cheng X, Shan Q, Zhang Y, Liu J, Gao C and Qiu JL. 2014b. Simultaneous edit­ ing of three homoeoalleles in hexaploid bread wheat confers heritable resistance to powdery mildew. Nat Biotechnol 32:9 47–51. https://doi.org/10.1038/nbt.2969. Wang Z, Huang L, Wu B, Hu J, Jiang Z, Qi P, Zheng Y and Liu D. 2018. Characterization of an integrated active Glu-1Ay allele in common wheat from wild emmer and its potential role in flour improvement. Int J Mol Sci 19:923. Watson A, Ghosh S, Williams MJ, Cuddy WS,  Simmonds J,  Rey MD,  Hatta MAM,  Hinchliffe A, Steed A, Reynolds D, Adamski NM, Breakspear A, Korolev A, Rayner T,  Dixon LE,  Riaz A,  Martin W, Merrill Ryan M, Edwards D,  Batley J,  Raman R, Carter J,  Rogers C,  Domoney C,  Moore G,  Harwood W,  Nicholson P, Dieters MJ, DeLacy IH, Zhou J, Uauy G, Boden SA, Park RF, Wulff BBH and Hickey LT. 2018. Speed breeding is a powerful tool to accelerate crop research and breeding. Nat Plants 4(1): 23–29. https://doi.org/10.1038/s41477-017-0083-8. Wheat Initiative. 2013. An international vision for wheat improvement. www.wheat initia­ tive. org/vision-paper. Whitford R, Fleury D, Reif JC, Garcia M, Okada T, Korzun V and Langridge P. 2013. Hybrid breeding in wheat: technologies to improve hybrid wheat seed production. J Exp Bot 64:54 11–28. https://doi.org/10.1093/jxb/ert333. Winfield MO, Allen AM, Burridge AJ, Barker GLA, Benbow HR, Wilkinson PA, Coghill J, Waterfall C, Davassi A, Scopes G, Pirani A, Webster T, Brew F, Bloor C, King J, West C, Griffiths S, King I, Bentley AR, Edwards KJ. 2016. High-density SNP genotyping array for hexaploid wheat and its secondary and tertiary gene pool. Plant Biotechnol J 14(5):119 5–206. https://doi.org/10.1111/pbi.12485. Witcombe JR, Joshi A, Joshi KD and Sthapit BR. 1996. Farmers participatory crop improvement. I. Varietal selection and breeding methods and their impacts on bio­ diversity. Exp Agric 32:445–60. Wulff BBH and Dhugga KS. 2018. Wheat—the cereal abandoned by GM. Science 361: 451–2. https://doi.org/10.1126/science.aat5119. Würschum T, Langer SM, Longin CFH, Tucker MR and Leiser WL. 2018a. A three com­ ponent system incorporating Ppd D1, copy number variation at Ppd B1, and numer­ ous small effect quantitative trait loci facilitates adaptation of heading time in winter wheat cultivars of worldwide origin. Plant Cell Environ 41(6):1407–16. Würschum T, Liu G, Boeven PHG, Friedrich C, Longin H, Mirdita V, Kazman E, Zhao Y and Reif JC. 2018b. Exploiting the RHT portfolio for hybrid wheat breeding. Theor Appl Genet 131:1433–42. Xie W and Nevo E. 2008. Wild emmer: genetic resources, gene mapping and potential for wheat improvement. Euphytica, 164:603–14. Xu Y, An D, Li H and Xu H. 2011. Review: Breeding wheat for enhanced micronutrients. Can J Plant Sci 91: 231–7. https://doi.org/10.4141/CJPS10117. Yao Z, Zhao X, Li Y, Xu J, Bi A, Kang L, Xu D, Chen H, Wang Y, Wang YG, Liu S, Jiao C, Lu H, Wang J, Yin C, Jiao Y and Lu F. 2020. Triticum population sequencing provides insights into wheat adaptation. Nat Genet 52:1412–22.

32

Wheat Science

Zeven AC and Zhukovsky PM. 1975. Dictionary of cultivated plants and their centers of diversity. Wageningen: PUDOC, p. 219. Zhang H, Mittal N, Leamy LJ, Barazani O and Song BH. 2017. Back into the wild— apply untapped genetic diversity of wild relatives for crop improvement. Evol Appl 10(1):5–24. https://doi.org/10.1111/eva.12434. Zhang Y, Liang Z, Zong Y, Wang Y, Liu J, Chen K, Qiu JL, and Gao C. 2016. Efficient and transgene-free genome editing in wheat through transient expression of CRISPR/ Cas9 DNA or RNA. Nat Commun 7:12 617. https://doi.org/10.1038/ncomms12617. Zhao TJ, Zhao SY, Chen HM, Zhao QZ, Hu ZM, Hou BK and Xia GM. 2006. Transgenic wheat progeny resistant to powdery mildew generated by Agrobacterium inocu­ lum to the basal portion of wheat seedling. Plant Cell Rep 25:1199–204. https://doi. org/10.1007/s00299-006-0184-8. Zhao Y, Li Z, Liu G, Jiang Y, Maurer HP, Würschum T, Mock H-P, Matros A, Ebmeyer E, Schachschneider R, Kazman E, Schacht J, Gowda M, Friedric C, Longin H and Jochen C. Reif JC. 2015. Genome-based establishment of a high-yielding heterotic pattern for hybrid wheat breeding. Proc Natl Acad Sci 112(51):156 24–29. https://doi. org/10.1073/pnas.1514547112. Zohary D and Hopf M. 2000. Domestication of plants in the old world: The origin and spread of cultivated plants in West Asia; Europe, and the Nile Valle. New York: Oxford University Press. Zohary D, Hopf M and Weiss E. 2012. Domestication of plants in the old world: The origin and spread of domesticated plants in Southwest Asia, Europe, and the Mediterranean Basin. Oxford: Oxford University Press.

2 Wheat Production, Trade, Consumption, and Stocks Global Trends and Prospects Sendhil R., Kiran Kumara T. M., Ankita Kandpal, Binita Kumari, and Soumya Mohapatra CONTENTS 2.1 2.2 2.3 2.4 2.5

Introduction...................................................................................................... 33

Global Trends in the Area, Production, and Productivity of Wheat ............... 34

Regional Scenario in the Area, Production, and Productivity of Wheat......... 36

Productivity Level Vis-a-Vis Efficiency Gap................................................... 42

Trends in Wheat Trade..................................................................................... 43

2.5.1 Export Scenario ................................................................................... 43

2.5.2 Import Scenario...................................................................................44

2.6 Trends in Wheat Stocks ...................................................................................46

2.7 Trends in Wheat Consumption and Closing Stocks ........................................ 48

2.8 Production and Trade-Related Constraints in Wheat ...................................... 50

2.9 Conclusion and Policy Imperatives.................................................................. 52

References.................................................................................................................. 53

2.1 Introduction Wheat is the most worldwide grown cereal grain (Nelson, 1985) serving as the staple food of the global population. Wheat is not only rich in starch but also rich in pro­ tein, vitamins, minerals, dietary fibres, and phytochemicals (Shewry and Hey, 2015). About 13–17% of the wheat grain is bran, of which 53% is fibre content (Sramkova et al., 2009). More than 800 million population worldwide suffers from chronic hun­ ger with a maximum population hailing from sub-Saharan Africa and South Asia (Sharma et al., 2016). As per the FAO statistics, 2021, the percent of undernourishment is 9.8% worldwide while 11.7% of the world’s population suffers from severe food insecurity leading to undernutrition. Studies suggest that malnutrition can be success­ fully addressed if the diet of the people consists of balanced proportions of proteins, carbohydrates, fat, and micronutrients (Collins, 2007). Wheat is rich in all these nutri­ ents and provides nearly 55% of carbohydrates and 20% of calories consumed around the world (Breiman and Graur, 1995; Opine et al., 2015). Thus, it is evident that wheat plays an important role in alleviating hunger and malnutrition in the world. DOI: 10.1201/9781003307938-2

33

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Owing to the importance of wheat in alleviating global hunger, the production of wheat in the world must increase to 840 million tonnes by 2050 (Sharma et al., 2015). However, the shrinking of land and other essential resources is one of the major chal­ lenges to achieving the required wheat production. Wheat is placed first among the cereals in terms of consumption due to its nutritive value and relative ease in its har­ vest, storage, transport, and processing as compared to other grains (Posner, 2000). The demand for wheat has been growing, and it is predicted that the global demand would increase by about 60% by the year 2050 (Rosegrant and Agcaoili, 2010). Wheat production faces several biotic and abiotic stresses, which pose threat to achieving the production targets. Also, the productivity of the crop is declining every year. Everincreasing population combined with declining farm sizes also poses a serious threat to fulfilling the increasing demand for grain. Thus, there is a need to have a deep insight into the production, consumption, and trade of the crop in the world. In the present chapter, we analyzed the production, trade, consumption, and stock scenario across major wheat-growing countries/regions in terms of growth trends using the data sourced from the DES (2022), FAOSTAT (2022), and USDA (2022). The chapter has also highlighted the constraints which hamper the production and trade in the wheat-growing regions, and various policies which can help to overcome those constraints have been suggested.

2.2 Global Trends in the Area, Production, and Productivity of Wheat Data on area, production, and productivity of wheat were collected and compiled for the period of 1970 triennium ending (TE) to 2020 TE from the FAOSTAT, 2022 data­ base for required analysis and policy formulations. The inference can be drawn from Figure 2.1 that at the global level, the acreage of wheat has oscillated between 200 and 240 Mha between 1970 and 2020 TE, with a peak growth rate during 1982 TE (240 Mha) and gradually slowed down toward the current acreage of 220 Mha. By 2020, wheat was the most widely grown crop in the world, with a global area of 220 Mha, showing an increasing trend in the area of about 10% since 2019 TE. The area under wheat has been more or less stagnant after the 1990 TE which can be attributed to the continuous increasing and declining trends in area in the case of Asian and European countries, respectively. In terms of production, global production of wheat amounted to over 765 million metric tonnes, which is an increase of over 30 million tonnes as compared to 2019 TE. Despite the oscillating pattern of wheat acreage, there has been a continuous increasing trend in global wheat production since 1996 TE (+36%) due to a substantive rise in yield levels (+38%). Asian and European countries are the major contributors to the global production of wheat with a steady growth pattern in the respective production levels. Asian coun­ tries occupy the largest share in global wheat production (45%, 2020 TE), followed by European (35%, 2020 TE) and American (15%, 2020 TE) countries with small shares by Africa and Oceania (3–4%). The relative production share of all the coun­ tries has remained more or less similar since the last quarter century. Interestingly, in the United States, 5–6% decline in wheat production was observed mainly due to the changing cropping pattern and production technologies. The global yield level of wheat has shown a steady growth of about 1.5 to 3.5 tonnes/ha, quadrupling the production

0

Africa

Americas

Asia

Europe

Oceania

400

300

200

100

Oceania

4500

4000

3500

3000 TE 2016

TE 2014

TE 2012

TE 2010

TE 2008

TE 2006

TE 2004

TE 2002

TE 2000

TE 1998

TE 1996

TE 1994

TE 1992

TE 1990

TE 1988

TE 1986

TE 1984

TE 1982

TE 1980

TE 1978

TE 1976

TE 1974

TE 1972

TE 1970

TE 2020

500 TE 2018

600

TE 2020

700

TE 2020

800

TE 2018

TE 2016

TE 2014

Oceania

TE 2018

TE 2016

TE 2014

Europe TE 2012

TE 2010

TE 2008

TE 2006

Europe

TE 2012

TE 2010

TE 2008

TE 2006

Asia TE 2004

TE 2002

TE 2000

Asia

TE 2004

TE 2002

TE 2000

Americas TE 1998

TE 1996

TE 1994

TE 1992

TE 1990

Americas

TE 1998

TE 1996

TE 1994

TE 1992

TE 1990

Africa TE 1988

TE 1986

TE 1984

Africa

TE 1988

TE 1986

TE 1984

World TE 1982

TE 1980

TE 1978

TE 1976

TE 1974

World

TE 1982

TE 1980

TE 1978

TE 1976

TE 1974

TE 1972

TE 1970

0

TE 1972

Produc on (million tonnes) 0

TE 1970

/ hecatre)

Area (million hecatres)

Wheat Production, Trade, Consumption, and Stocks 35

300

250

200

150

100

50

World

FIGURE 2.1 Global trends in the (a) area, (b) production, and (c) productivity for wheat-growing regions.

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level over the period. All the regions have registered increasing yield patterns over the period of time, except Oceania. With the relative stability in global wheat acreage over the past half century, the yield level of wheat has shown a consistent rise which can be explained by a modest increase in the production level (Erenstein et al., 2022).

2.3 Regional Scenario in the Area, Production, and Productivity of Wheat Although wheat is grown all over the world, five regions, that is, Asia, America, Europe, Africa, and Oceania, are considered for the present study (Table 2.1). Asia contributes to the maximum acreage (45.79%) under wheat crop, followed by Europe (28.46%) and America (16.36%); whereas, Africa and Oceania have a smaller share of the global wheat area (4–5% each). All the five regions have exhibited a positive growth rate during 2020 TE. Asia has shown the highest growth rate in the area during the study period (47.06%), followed by Oceania (15.24%) and Africa (9.02%); however, Europe and America have shown a continuous declining trend in the area. In the case of the Asian region, South Asia has registered the highest growth rate in acreage (66.85%), followed by Central Asia, but, East Asia, Southeast Asia, and West Asia have shown a declining trend in 2020 TE. The maximum decrease in the wheat area was observed in South Africa (1.38 Mha, −72.38%), followed by South Europe (6.69 Mha, −56.75%) and the Middle African region (0.02 Mha, −48.07%). Similarly, the increasing trend in wheat acreage was highest in the case of West Africa (0.06 Mha, +399.56%), followed by North Europe (0.43 Mha, +173.76%). Among the sub-regions, South Asia occupies the largest share of global wheat area in 2020 TE (22.92%), followed by East Europe (20.05%) and North America (11.65%). The continuous rise in the wheat area may be attributed due to the Green Revolution which combined high-yielding varieties of wheat with input and irrigation

TABLE 2.1 Trends in Wheat Area for Major Global Regions Area (Mha)

Region

Global Share (TE TE 1970 TE 1980 TE 1990 TE 2000 TE 2010 TE 2020 2020, %)

TE 1970 to TE 2020 (% Change)

Africa

9.05

8.31

8.26

8.91

9.38

9.86

4.56

9.02

East Africa Middle Africa North Africa South Africa West Africa

1.27

0.75

0.94

1.31

1.88

2.13

0.99

68.49

0.03

0.02

0.01

0.01

0.01

0.01

0.01

−48.07

5.84

5.68

5.41

6.71

6.76

7.12

3.29

22.05

1.91

1.85

1.85

0.82

0.67

0.53

0.24

−72.38

0.01

0.01

0.05

0.06

0.06

0.07

0.03

399.56

37

Wheat Production, Trade, Consumption, and Stocks TABLE 2.1 (Continued) Area (Mha)

Region Americas Central America North America South America Asia Central Asia East Asia South Asia Southeast Asia West Asia Europe East Europe North Europe South Europe West Europe Oceania Australia and New Zealand Melanesia World

Global Share (TE TE 1970 TE 1980 TE 1990 TE 2000 TE 2010 TE 2020 2020, %)

TE 1970 to TE 2020 (% Change)

37.42 0.87

46.47 0.73

49.00 1.02

41.88 0.72

39.11 0.77

35.39 0.57

16.36 0.26

−5.42 −35.08

28.64

36.41

38.47

33.02

29.99

25.20

11.65

−12.04

7.91

9.33

9.51

8.15

8.34

9.63

4.45

21.85

67.35 –

79.58 –

83.68 –

99.21 12.11

99.56 16.46

99.04 14.21

45.79 6.57

47.06 17.30

25.94 29.72 0.07

29.90 37.18 0.09

30.67 40.34 0.12

28.91 44.50 0.09

24.56 46.62 0.10

24.39 49.58 0.06

11.28 22.92 0.03

−5.98 66.85 −10.01

11.62 94.00 73.85

12.41 86.41 67.93

12.55 75.30 56.15

13.59 53.87 34.45

11.82 59.56 40.22

10.79 61.55 43.37

4.99 28.46 20.05

−7.09 −34.52 −41.27

1.60

1.94

2.97

3.85

4.28

4.39

2.03

173.76

11.79

9.23

8.00

6.88

5.68

5.10

2.36

−56.75

6.75

7.32

8.18

8.69

9.37

8.69

4.02

28.62

9.06 9.06

10.98 10.98

9.06 9.06

12.06 12.06

13.38 13.38

10.44 10.44

4.83 4.83

15.24 15.24

0.00 216.87

0.00 231.76

0.00 225.31

0.00 215.93

0.00 220.98

0.00 216.28

0.00 100.00

131.96 −0.27

Data source: FAOSTAT (2022) Note: The bold values indicate the data for the whole region. The subsequent rows indicate the data for the sub-regions.

management practices. Expansion and intensification of the wheat crop are mostly dominated by South Asian and some European countries thereby necessitating the scope to divert the improved production practices toward other global regions. Table 2.2 presents the global production trends of wheat. The production level of wheat had witnessed a rising trend over a period of time. Global wheat production has increased twice from 315.41 Mt during 1970 TE to 752.68 Mt during 2020 TE, corre­ sponding to a substantial growth of 138.64%. In terms of the global share of wheat pro­ duction, Asia holds the largest proportion (44.75%), followed by Europe (33.81%) and America (15.46%); together, they contribute about 94% to global wheat production. All five regions showed a positive growth rate in wheat production during the study period.

38

Wheat Science

TABLE 2.2 Trends in Wheat Production for Major Global Regions Production (Mt)

Region Africa East Africa Middle Africa North Africa South Africa West Africa Americas Central America North America South America Asia Central Asia East Asia South Asia Southeast Asia West Asia Europe East Europe North Europe South Europe West Europe Oceania Australia and New Zealand Melanesia World

Global Share (TE TE 1970 TE 1980 TE 1990 TE 2000 TE 2010 TE 2020 2020, %)

TE 1970 to TE 2020 (% Change)

8.05 1.12 0.03

8.83 0.98 0.02

13.25 1.51 0.01

16.15 1.86 0.02

22.33 3.43 0.02

26.95 5.99 0.02

3.58 0.80 0.00

234.67 434.92 −44.09

5.51

6.01

9.19

12.13

16.91

19.00

2.52

245.07

1.38

1.79

2.48

2.04

1.86

1.85

0.25

34.45

0.02 66.17 2.40

0.03 91.53 2.68

0.06 105.21 4.03

0.11 112.30 3.26

0.10 114.29 3.94

0.10 116.34 3.06

0.01 15.46 0.41

333.73 75.83 27.75

54.46

76.28

83.95

90.04

89.10

84.59

11.24

55.32

9.31

12.57

17.23

19.00

21.25

28.69

3.81

208.22

74.02 –

130.57 –

193.39 –

256.76 15.06

286.11 22.68

336.86 21.81

44.75 2.90

355.08 44.87

29.22 32.08

58.17 52.26

93.25 74.52

108.64 105.34

115.47 119.63

134.53 150.76

17.87 20.03

360.36 369.92

0.04

0.08

0.14

0.10

0.18

0.11

0.02

209.79

12.68 155.69 103.50

20.07 189.39 121.04

25.47 216.96 123.81

27.63 180.13 71.18

28.15 226.18 110.01

29.65 254.45 144.45

3.94 33.81 19.19

133.77 63.43 39.57

6.01

9.80

19.26

25.37

28.07

27.88

3.70

363.82

21.22

22.57

22.97

20.43

19.14

19.99

2.66

−5.81

24.96

35.97

50.92

63.15

68.96

62.13

8.25

148.94

11.48 11.48

15.35 15.35

14.58 14.58

23.31 23.31

19.34 19.34

18.08 18.08

2.40 2.40

57.55 57.55

0.00 315.41

0.00 435.68

0.00 543.40

0.00 588.65

0.00 668.25

0.00 752.68

0.00 100.00

−38.83 138.64

Data source: FAOSTAT (2022) Note: The bold values indicate the data for the whole region. The subsequent rows indicate the data for the sub-regions.

39

Wheat Production, Trade, Consumption, and Stocks

The highest growth rate was observed in the case of Asia (+262.84 Mt, 336.86%), followed by Africa (+18.9 Mt, 234.67%) and America (+50.17 Mt, 75.83%). Positive growth in production was observed in almost all the sub-regions, except Middle Africa (−44.09%), Melanesia (−38.83%), and Southern Europe (−5.81%) during the study period. Within the sub-regions, the highest growth rate in production was reg­ istered in East Africa (+4.87 Mt, 434.92%, South Asia (+118.68 Mt, 369.92%), North Europe (+21.87 Mt, 363.82%), and West Africa (+0.08 Mt, 333.73%). Although acre­ age under wheat was continuously fluctuating over the period, production levels in all the regions have witnessed a positive trend due to high-yielding and climate-resilient wheat varieties and improved management techniques. The global productivity level of wheat witnessed an increasing trend from 1,455 kg/ha during 1970 TE to 3,480 kg/ha during 2020 TE (Table 2.3), with a growth rate of 139.18%. There was a positive change observed in each region during the study period; Asia witnessed the highest growth (+2,302 kg/ha, 209.47%), followed by TABLE 2.3 Trends in Wheat Productivity for Major Global Regions Productivity (kg ha−1)

Region Africa East Africa Middle Africa North Africa South Africa West Africa Americas Central America North America South America Asia Central Asia East Asia South Asia Southeast Asia

TE 1970

TE 1980 TE 1990 TE 2000

TE 2010

TE 1970 – TE 2020 (% TE 2020 Change)

Rank (TE 2020)

891 883

1,064 1,312

1,610 1,606

1,809 1,428

2,373 1,825

2,733 2,803

206.74 217.28

17 15

1,095

754

938

1,434

1,327

1,185

8.26

24

943

1,059

1,705

1,801

2,492

2,666

182.67

18

724

969

1,320

2,475

2,775

3,530

387.83

7

1,673

1,993

1,141

1,856

1,716

1,456

−12.98

23

1,781 2,742

1,969 3,664

2,135 3,972

2,681 4,561

2,925 5,119

3,288 5,408

84.60 97.23

12 4

1,918

2,094

2,162

2,728

2,972

3,359

75.15

10

1,182

1,350

1,809

2,328

2,552

2,982

152.23

14

1,099 –

1,641 –

2,310 –

2,589 1,246

2,873 1,373

3,401 1,535

209.47 23.13

9 22

1,126 1,079

1,945 1,405

3,038 1,847

3,758 2,367

4,702 2,565

5,517 3,040

389.82 181.82

3 13

533

879

1,110

1,063

1,730

1,862

249.17

19

(Continued)

40

Wheat Science

TABLE 2.3 (Continued) Productivity (kg ha−1)

Region

TE 1970

TE 1980 TE 1990 TE 2000

TE 2010

TE 1970 – TE 2020 (% TE 2020 Change)

West Asia Europe East Europe North Europe South Europe West Europe Oceania Australia and New Zealand Melanesia World

1,092 1,656 1,402

1,618 2,188 1,777

2,027 2,881 2,205

2,033 3,344 2,067

2,381 3,791 2,723

2,742 4,133 3,329

151.07 149.51 137.53

16 5 11

3,749

5,056

6,461

6,594

6,565

6,323

68.64

2

1,800

2,446

2,873

2,973

3,360

3,920

117.81

6

3,692

4,915

6,222

7,267

7,362

7,149

93.65

1

1,259 1,259

1,410 1,410

1,609 1,609

1,932 1,932

1,436 1,436

1,725 1,725

37.04 37.04

21 20

2,815 1,455

1,498 1,880

1,061 2,409

1,863 2,726

– 3,023

719 3,480

-74.44 139.18

25 8

Rank (TE 2020)

Data source: FAOSTAT (2022) Note: The bold values indicate the data for the whole region. The subsequent rows indicate the data for the sub-regions.

Africa (+1,842 kg/ha, 206.74%) and Europe (2,477 kg/ha, 149.51%). Among the sub­ regions, all witnessed an increasing pattern in yield, except Melanesia (−74.44%) and West Africa (−12.98%). East Asia (+4,391 kg/ha, 389.82%), South Africa (+2,806 kg/ ha, 387.83%), Southeast Asia (+ 1,329 kg/ha, 249.17%), and East Africa (+1,920 kg/ha, 217.28%) are some of the sub-regions with highest growth rate over the period of time. The positive growth trend in yield levels of wheat can be attributed to the adoption of good agricultural practices, varietal improvement in various national and interna­ tional institutions, and the adoption of modern cultivation practices at the farmers’ level (Joshi et al., 2007). The top 20 countries contributing highest to the global area, production, and pro­ ductivity of wheat in the year 2020 TE are presented in Figure 2.2. India occupies the first position in terms of area (39.21%), followed by Russian Federation (33%), China (31%), the United States (21%), and Kazakhstan (15.68%). However, in terms of production, China takes the top slot with 135 M tonnes (17.64% of total production), followed by India (110 Mt) and Russian Federation (78 Mt). The high production level of wheat in China can be attributed to the adoption of resource conservation technologies as well as the improved agricultural environment in the country (Wang et  al., 2009). The average productivity of wheat in 2020 TE was highest in New Zealand (9,100 kg/ha), followed by Belgium (8,900 kg/ha) and the Netherlands (8,100 kg/ha). These countries accomplished high productivity levels despite occupying very less area under wheat. The main reasons for higher wheat

Wheat Production, Trade, Consumption, and Stocks

41

35000 30000

Area ('000 ha)

25000

20000 15000 10000 5000 0

140000 120000

tonnes)

100000 80000 60000 40000 20000 0

10000 9000

)

8000 7000 6000 5000 4000 3000 2000 1000 0

FIGURE 2.2 Top 20 countries in the (a) wheat area, (b) production, and (c) productivity (TE 2020). Data source: FAOSTAT (2022)

42

Wheat Science

yield in New Zealand can be better cultivar parameters, canopy structure, higher bio­ mass production, and ultimately higher yield (Senapati and Semenov, 2019). India, with the first rank in the area and second in production, failed to bag a position among the top 20 countries in terms of productivity. Low wheat yield levels in India could be due to increasing heat and other climatic stress, improper irrigation management as well as a threat from several forms of diseases (wheat rust), and adverse selection of crop varieties (Joshi et al., 2007).

2.4 Productivity Level Vis-a-Vis Efficiency Gap Figure 2.3 depicts the comparison between the productivity and efficiency gap for all the wheat-growing countries, as productivity is considered one of the major determi­ nants of efficiency level. Efficiency gap (EG) is a ratio that explains the difference in the crop yield level of a particular region and the yield level of the region with the highest productivity, that is, benchmark yield level (Sendhil et al., 2022; Singh et al., 2017). EG is computed by using the following formula: EG  =  1 – (Actual yield ÷ Benchmark yield) × 100 It can be inferred from Figure 2.3 that New Zealand is considered the benchmark country for EG analysis with the highest productivity of 9,100 kg/ha (2020 TE) owing to the wide cultivation of winter wheat which is highly productive (having a long duration) in comparison to the spring wheat (have a short duration and cul­ tivated in regions like India). EG is maximum for Somalia (more than 99%) and minimum for the Netherlands. China, the largest producer of wheat, registered an EG of more than 60% owing to the type of wheat under cultivation. The range of EG among countries calls for region-specific research interventions for augment­ ing productivity and minimizing the yield gap as well as the realization of higher yield potential.

10000

120

9000 100

8000

80

6000 60

5000

4000 40

3000 2000

20

0

New Zealand Netherlands United Kingdom Germany Egypt Kuwait Chile Saudi Arabia Czechia China Mexico Slovenia Namibia Serbia Poland Uzbekistan Japan Bosnia and Herzegovina Norway Italy Republic of Korea Mali North Macedonia Oman Lebanon United States of America Argentina Uruguay Montenegro Nepal Pakistan Iraq Russian Federation Republic of Moldova Portugal Kyrgyzstan Madagascar Armenia Cyprus Colombia Guatemala Afghanistan Jordan Tunisia Israel Myanmar Syria Zimbabwe Australia Peru Uganda Bhutan Mongolia Democratic People's Republic… Mozambique Thailand Botswana Nigeria Burundi Lesotho New Caledonia Somalia

1000

Productivity (kg/ha)

Efficiency Gap (%)

FIGURE 2.3 Productivity levels (kg ha−1) vis-à-vis efficiency gap (%). Data source: FAOSTAT (2022)

0

Efficiency Gap (%)

Productivity (kg/ha)

7000

43

Wheat Production, Trade, Consumption, and Stocks

2.5 Trends in Wheat Trade 2.5.1 Export Scenario The world’s biggest wheat producers have attained self-sufficiency in wheat produc­ tion, which requires an active global trade linking the areas with surplus produc­ tion with the deficit areas. Table 2.4 presents the pattern of wheat exports across TABLE 2.4 Trends in Wheat Exports for Major Global Regions Exports (’000 tonnes) Region

TE 1970

TE 1980

TE 1990

TE 2000

TE 2010

TE 2020

Africa East Africa Middle Africa North Africa South Africa West Africa Americas Caribbean Central America North America South America Asia Central Asia East Asia South Asia Southeast Asia West Asia Europe East Europe North Europe South Europe West Europe Oceania Australia and New Zealand Melanesia World

52.25 40.77 0.00 2.71 8.56 0.20 26,595.57 0.00 99.08

137.08 6.29 0.19 0.17 128.94 1.49 52,270.60 0.00 17.64

585.31 0.06 0.08 0.82 582.14 2.21 56,240.99 2.05 134.08

187.08 59.55 0.00 2.08 105.04 20.41 55,856.66 0.34 338.70

144.83 37.83 0.42 5.92 84.89 15.76 53,942.87 0.15 992.49

149.68 11.48 0.00 6.89 125.91 5.40 61,637.45 0.39 612.04

24,114.59

48,792.29

51,313.85

45,303.68

44,373.30

49,163.08

2,381.91

3,460.67

4,791.01

10,213.94

8,576.93

11,861.94

186.44 – 6.43 142.73 15.82

1435.44 – 1.66 422.81 16.72

2,644.58 – 29.90 56.49 43.70

5,661.96 3,523.21 3.97 282.74 5.04

5,799.80 4487.75 44.86 306.83 33.21

7,130.01 5,712.30 5.37 1,104.37 38.65

21.45 13,667.72 6,255.56 370.47 731.39 6,310.30 6,124.09 6,124.09

994.24 14,567.11 3,340.07 1,047.90 224.05 9,955.09 10,883.08 10,883.08

2,514.49 31,317.77 3,123.81 4,801.47 2,238.34 21,154.16 11,381.34 11,381.34

1,847.00 35,499.16 6,372.60 5,102.73 823.41 23,200.42 16,498.93 16,498.93

927.15 68,344.59 30,775.40 6,954.15 1,858.24 28,756.80 13,058.64 13,058.59

269.33 110,166.13 72,153.89 7881.67 2231.90 27,898.68 10,783.39 10,781.84

0.00 46,626.07

0.00 79,293.31

0.00 102,170.00

0.00 113,703.79

0.05 141,290.73

1.55 189,866.67

Data source: FAOSTAT (2022) Note: The bold values indicate the data for the whole region. The subsequent rows indicate the data for the sub-regions.

44

Wheat Science

40000 35000

Exports ('000 tonnes)

30000 25000

20000 15000 10000 5000 0

FIGURE 2.4 Top 20 countries in wheat exports (TE 2020).

major global regions and subregions. Total world exports of wheat in 2020 TE were around 190 Mt, out of which Europe registered the highest quantity of exports (110 Mt), followed by America (61.63 Mt) and Asia (7.13 Mt). All the regions increased their exports during the study period (1970 TE to 2020 TE), except Oceania, thereby raising the global exports from 141.29 Mt in 2019 TE to 189.86 Mt in 2020 TE. Among the subregions, East Europe registered the highest level of wheat export, followed by North America, West Europe, and South America. Though Asian coun­ tries have been ranked top in terms of wheat area and production, the consump­ tion demand has increased and is attributed to the rising population and economic growth. Therefore, Asian countries are not able to realize their full export potential (Sendhil et al., 2022). Among the major wheat-exporting countries, Russian Federation tops the list with an export quantity of 38.76 Mt (23.92% of global export) during 2020 TE (Figure 2.4), followed by the United States (25.49 Mt), and Canada (24.87 Mt). In order to bridge the gap between consumption demand and availability of wheat, trade plays an impor­ tant role to diversify the dynamic production and consumption pattern.

2.5.2 Import Scenario Considering the dynamism of wheat processing and consumption pattern, substantial heterogeneity was found underlying wheat trade in each region. Table 2.5 indicates that the global import of wheat has registered positive growth (+140.65 Mt, 304.89%) during the study period, that is, 1970 TE to 2020 TE. All the regions and subregions covered in the study have witnessed an increased import trend over the past halfcentury, which can be attributed to the high levels of spatial variations between pro­ duction level and consumption preference of wheat.

45

Wheat Production, Trade, Consumption, and Stocks TABLE 2.5 Trends in Wheat Imports for Major Global Regions Imports (’000 tonnes) Region

TE 1970

TE 1980

TE 1990

TE 2000

TE 2010

TE 2020

Africa East Africa Middle Africa North Africa South Africa West Africa Americas Caribbean Central America North America South America Asia Central Asia East Asia South Asia Southeast Asia West Asia Europe East Europe North Europe South Europe West Europe Oceania Australia and New Zealand Melanesia Micronesia Polynesia World

3319.24 260.10 121.66

10556.35 613.96 308.10

14728.04 1,165.95 301.42

20970.35 2,376.13 448.61

35686.14 4,774.50 867.09

46516.92 5,670.83 1,792.40

2,485.22

8,114.54

11,951.83

14,414.52

23,036.77

27,848.24

54.85

44.33

324.85

761.19

1,586.36

2,332.33

397.40 5,413.64 555.46 308.65

1475.41 10,331.87 1,225.91 1,301.17

983.99 8,042.57 1,727.68 1,304.31

2,969.89 19,297.70 1,609.07 3,786.70

5,421.42 20,550.91 1,690.61 4,532.37

8873.12 23,988.26 1,756.11 6,231.16

31.40

3.82

479.31

2,076.96

2,606.85

2,452.11

4,518.13

7,800.97

4,531.26

11,824.97

11,721.08

13,548.88

19,439.81 –

28,684.46 –

44,617.02 –

44,095.68 1005.68

50,750.29 2,118.33

78,165.78 4,157.05

10,957.04 5,509.37 1,193.62

17,852.60 3,983.22 3,171.92

23,990.80 8,662.48 4,291.58

12,416.45 11,647.28 7,801.51

10,989.72 9,142.63 10,826.45

15,678.41 8,442.05 25,753.14

1,779.78 17,937.35 3,960.79

3,676.72 28,721.39 14,873.45

7,672.16 33,886.55 19,207.66

11,224.77 27,169.30 4,594.22

17,673.16 32,940.02 1,803.10

24,135.14 36,884.10 2,346.53

5,220.35

3,516.37

1,803.55

2,502.10

2,992.06

3,831.54

1,856.15

4,815.95

6,493.21

12,271.95

14,895.18

16,163.99

6,900.06 24.90 22.61

5,515.62 102.41 28.55

6,382.13 288.14 148.26

7,801.03 436.04 184.17

13,249.68 576.08 283.79

14,542.04 1,242.22 803.73

1.73 0.01 0.55 46,134.94

73.19 0.00 0.67 78,396.47

139.12 0.00 0.76 101,562.32

251.67 0.00 0.20 111,969.07

291.29 0.00 0.99 140,503.43

437.17 0.00 1.32 186,797.28

Data source: FAOSTAT (2022) Note: The bold values indicate the data for the whole region. The subsequent rows indicate the data for the sub-regions.

46

Wheat Science

12000

Imports ('000 tonnes)

10000 8000 6000 4000 2000

0

FIGURE 2.5 Top 20 countries in wheat imports (TE 2020).

Asia is the major importer of wheat (41.84%) in 2020 TE, followed by Africa (24.89%), Europe (19.74%), and America (12.83%). Asia, being the largest pro­ ducer of wheat, surprisingly tops the list of major wheat-importing regions due to the increase in income, urbanization, change in food preferences and lifestyles as well as the inclusion of high-value foods in the dietary patterns (Drewnowski et al., 2009). Among the subregions, North Africa is the major importer of wheat (27.84 Mt) owing to the region’s strong population growth, climate-constrained production, and shift in the dietary pattern which have forced the country to heavily rely on imports (Nigatu and Motamed, 2015). Egypt, Indonesia, Turkey, and Italy are some of the major wheat-importing countries (Figure  2.5) during 2020 TE and account for about 40% of global wheat imports. Though these countries are self-sufficient in terms of wheat production, still they are the major importers of wheat grain, and, by using the advanced processing infrastructures, they become the leading exporter of wheat flour in the world.

2.6 Trends in Wheat Stocks Stocking the surplus quantity of food grains in the central pool aids one country to meet the operational requirements in times of food crisis or increased price variabil­ ity, especially in the case of the importing countries. It can be inferred from Table 2.6 that the pattern of wheat-opening stock for all the global regions has increased over the period of time (1970 TE to 2020 TE) due to which the global opening stock has registered a growth of about 135.61% (161.85 Mt in 1970 TE to 381.35 Mt in 2020 TE). Asia contributed the highest to the global opening stock of wheat (212.98 Mt, 55.85%), followed by Europe (87.9 Mt, 23.04%) and America (50.56 Mt, 13.25%). Among the subregions, East Asia ranks at the top in terms of wheat opening stock (135.12 Mt, 35.45%), which could be due to the strong governmental policies as well as new-fangled buffer stock operations (Lin et al., 2022).

47

Wheat Production, Trade, Consumption, and Stocks TABLE 2.6 Trends in Wheat Opening Stocks for Major Global Regions Opening Stocks (’000 tonnes) Region

TE 2012 TE 2013 TE 2014 TE 2015 TE 2016 TE 2017 TE 2018 TE 2019

Africa East Africa Middle Africa North Africa South Africa West Africa Americas Caribbean Central America North America South America Asia Central Asia East Asia South Asia Southeast Asia West Asia Europe East Europe North Europe South Europe West Europe Oceania Australia and New Zealand Melanesia Polynesia World

20,064.0 3,703.0 196.2

20,358.9 21,189.7 21,006.3 3,831.8 4,024.0 3,977.2 212.0 235.6 277.9

22,922.6 23,851.6 3,955.4 3,883.4 354.1 441.8

24,729.4 24,886.5 3,704.5 3,346.9 556.5 652.1

12,654.6

13,027.4 14,041.5 14,414.0

16,721.3 17,861.6

18,730.3 18,896.3

497.9

686.4

899.5

933.8

654.7

509.5

342.9

478.9

3,012.4 12,899.1 181.1 1,053.4

2,601.3 10,628.0 176.5 961.5

1,989.1 18,809.1 164.5 959.2

1,403.4 28,179.5 193.1 945.6

1,237.1 40,124.1 248.8 1,021.6

1,155.3 45,829.0 263.9 1,172.6

1,395.2 48,584.9 257.1 1,203.9

1,512.3 50,566.5 193.6 1,224.0

1,894.8

2,263.2

12,154.8 22,305.7

32,967.9 38,388.4

42,162.3 45,298.0

9,769.8

7,226.7

5,530.6

5885.8

4,961.6

4,735.1

6,004.0

3,850.9

112,248.8 11,5112.4 12,3764.4 13,7314.9 15,7540.4 17,7601.3 19,7728.0 212,985.8 6458.6 5056.2 5896.0 4947.0 7299.6 9895.5 12803.4 14104.0 63108.0 28139.3

62943.9 29593.7

65564.5 29168.7

73210.9 31569.4

87210.0 31546.6

103214.5 120753.8 135127.1 32289.5 31934.1 32675.1

3607.4

3886.7

3895.3

3643.5

3309.9

3505.2

3743.8

4446.1

10935.5 12288.7 5817.3 4552.1

13632.0 11888.1 5642.7 4152.7

19239.9 32724.6 13075.9 4259.0

23944.0 56204.9 20867.5 5776.8

28174.3 81925.2 28730.5 8002.1

28696.6 85373.8 29614.0 8703.1

28492.7 88931.5 29824.7 8474.7

26633.5 87901.2 28123.2 6847.1

617.3

712.2

4251.3

7960.7

11631.5

13551.9

15209.2

17498.6

1302.0

1380.6

11138.5

21599.9

33561.2

33504.7

35423.0

35432.3

4355.5 4176.9

5144.9 4976.6

5945.1 5771.6

5433.5 5255.9

5040.3 4873.3

4735.0 4584.0

5089.9 4981.3

5015.6 4937.7

178.3 167.9 173.2 177.3 166.6 150.6 108.3 77.7 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 161856.0 163132.3 202432.9 248139.1 307552.6 337390.7 365063.7 381355.7

Data source: FAOSTAT (2022) Note: The bold values indicate the data for the whole region. The subsequent rows indicate the data for the sub-regions.

48

Wheat Science

140000

Opening Stocks ('000 tonnes)

120000

100000

80000

60000

40000

20000

0

FIGURE 2.6 Top 20 countries in wheat opening stocks (TE 2019).

Figure 2.6 depicts the top 20 countries in wheat opening stocks in 2019 TE, and it can be understood that China alone contributes more than 85% to the global wheat opening stock, followed by the United States, Germany, and Turkey. The highest opening stock of China could be due to the population explosion and to meet their consumption requirement as well as the largest foreign reserve of the country (Li et al., 2014). However, India, being the second largest producer of wheat, registered an opening stock of less than 200 Mt, which sheds light on the need for an efficient management of the wheat supply chain as well as strengthening the existing buffer stock operations (Saini and Kozicka, 2014).

2.7 Trends in Wheat Consumption and Closing Stocks Globally, wheat is one of the cheapest sources of all the required nutrients and micronutrients; therefore, it is the staple food for a majority of the regions in the world. Asian regions like South Asia and East Asia top the list of the consumption levels of wheat (Table 2.7), followed by the European Union and the Soviet Union. China has been ranked first in terms of wheat consumption (148 Mt) in 2021/22, followed by the European Union (109.75 Mt) and India (107.91 Mt), which could be due to various factors like population growth, surplus production and access to the pub­ lic, change in consumer preference, and rising income level. (Sendhil et  al., 2020;

49

Wheat Production, Trade, Consumption, and Stocks TABLE 2.7 Trends in Wheat Consumption and Ending Stocks (’000 Tonnes) Region Consumption North America South America European Union Other Europe Former Soviet Union − 12 Middle East North Africa Sub-Saharan Africa East Asia South Asia Southeast Asia Oceania Others Ending Stocks North America South America European Union Other Europe Former Soviet Union –12 Middle East North Africa Sub-Saharan Africa East Asia South Asia Southeast Asia Oceania Others Consumption Algeria Brazil Canada China Egypt The European Union India Indonesia Iran

2018/19

2019/20

2020/21

2021/22

46,606 28,695 106,300 20,697 76,435

47,586 29,465 107,250 20,421 75,560

46,809 29,685 104,750 18,725 78,645

47,433 29,430 109,750 20,565 78,110

59,919 46,100 30,319

62,860 46,250 32,975

64,322 46,720 34,583

63,640 47,020 34,335

137,750 138,996 26,165 10,610 3,614

138,638 139,880 26,355 9,410 3,694

162,368 148,436 26,030 9,435 3,818

161,151 155,592 26,385 9,955 3,565

36,030 5,876 15,798 3,224 14,883

33,869 6,786 13,110 3,850 13,141

28,929 6,651 10,693 2,497 18,139

21,823 4,921 14,361 2,869 21,693

14,412 15,537 2,926

17,849 14,357 4,220

16,851 11,142 4,486

14,185 11,253 4,039

141,028 21,466 6,186 4,769 408

153,011 28,203 6,240 3,029 548

147,013 34,242 5,728 4,640 614

144,955 28,966 5,401 5,161 474

10,750 11,900 9,120 125,000 20,100 106,300

10,950 11,900 9,750 126,000 20,300 107,250

11,150 11,800 9,133 150,000 20,600 104,750

11,370 11,750 9,500 148,000 20,500 109,750

95,629 10,600 16,100

95,403 10,300 17,200

102,217 10,300 17,400

107,911 10,600 18,200 (Continued)

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Wheat Science

TABLE 2.7 (Continued) Region

2018/19

2019/20

2020/21

2021/22

Morocco Pakistan Russia Turkey Ukraine The United Kingdom The United States Others Ending Stocks Algeria China The European Union India Iran Russia Ukraine The United States Others

10,700 25,400 40,500 18,800 8,800 15,417

10,400 25,500 40,000 20,000 8,300 15,196

10,400 26,300 42,500 20,600 8,700 13,455

10,600 27,700 41,750 20,200 10,000 15,300

29,986 177,104

30,436 181,459

30,476 184,545

30,533 183,267

5,219 138,088 15,798

5,358 150,015 13,110

4,992 144,120 10,693

3,917 141,916 14,361

16,992 4,936 7,778 1,555 29,386 62,791

24,700 4,786 7,228 1,504 27,985 63,527

27,800 4,336 11,380 1,505 23,001 63,798

21,467 4,786 12,088 5,842 17,962 57,762

Data source: USDA (2022)

Svanidze et al., 2019; Nasurudeen et al., 2006). East Asia occupies the top position in terms of global closing stock of wheat (144.96 Mt) out of which China alone con­ tributes 141.92 Mt (98%). The overall analysis between 2018/19 and 2021/22 indicates that the consumption of wheat across regions witnessed an increase. However, wheat closing stocks show a mixed pattern which is attributed to the change in production and consumption.

2.8 Production and Trade-Related Constraints in Wheat Agriculture production is significantly affected by several agronomic and socio­ economic challenges such as shrinking land base, declining land quality, inefficient resource use, low water use efficiency, and heat intolerance, and pest and disease infes­ tation has made the task of increasing the production even more complex. Although global wheat production has shown an increasing trend over the years, there are still significant gaps existing between the demand and supply of wheat. The adoption of intensive agricultural practices such as indiscriminate use of fertilizer, pesticides, and other inputs has threatened the sustainable production of wheat. In addition, detrimen­ tal impacts of climate change have further worsened the situation and made wheat farming uneconomical, especially for small and marginal holders. Delayed sowing in most of the wheat-growing regions, lack of access and availability of quality seeds due to weak institutional linkages, price volatility in the global wheat market, shrinking

51

Wheat Production, Trade, Consumption, and Stocks

Yield Plateau

Crop Intensification

Production Challenges

Changing Pest Complex

Growing Food Demand

Competition for Scarce Resources

Climate Change

Climate Change

Resource Degradation

Declining TFP

FIGURE 2.7 Challenges in wheat production. Source: Adapted from Ramadas et al. (2019).

farm holdings, and low resource use efficiency are major challenges and or constraints for wheat production. Further, total factor productivity in technologically advanced wheat growing is declining due to low technical and economic efficiency in resource use (Kandpal et al., 2022). Ramadas et al. (2019) highlighted the major production challenges in wheat in the Indian agricultural landscape (Figure 2.7). A plethora of empirical studies highlighted that trade can be a powerful engine for the growth and development of the economy (Hallaert and Munro, 2009). Countries that have sufficient infrastructure, efficient transport structure, minimal documenta­ tion, and other trade-related requirements often enjoy enormous benefits from the trade (Llanto, 2011). However, it is often challenging for developing nations to realize the maximum benefits from the trade due to various trade-related constraints. Roy and Banerjee (2010) highlighted the key factors which are obstacles to efficient trade and categorized them as ‘Gateway issues’ and ‘Behind-the-border issues’ (Figure 2.8). The volume of trade is primarily driven by behind-the-border issues, which are critical for higher growth in trade. In addition to this, Wilson et al. (2004) also identi­ fied that port efficiency, custom, regulatory environment, and lack of infrastructure are the key factors that act as impediments to regional trade in agriculture. Further, by employing a similar framework, Llanto (2011) identified the key constraints to trade in the South Asian region to be (i) high tariffs, (ii) inefficient logistics and port operation,

52

Wheat Science

Trade issues

Gateway

Behind-the border

Gateway issues

Customs and other formalities Transparency of regulations

Behind-the border issues

Quality and cost of transport infrastructure

Availability of multimodal logistics

Efficacy of regulatory authorities Capacity and efficiency of logistics Cost and quality of international transport linkages

Quality of logistical support Efficacy and transparency of regulations of domestic border crossings

FIGURE 2.8 Key issues in trade.

(iii) the presence of an unfavorable regulatory environment, and (iv) geo-political con­ flicts. Furthermore, high transaction costs and price volatility in the global wheat market are other major factors that significantly determine the wheat trade.

2.9 Conclusion and Policy Imperatives Sustainable intensification through the adoption of conservation practices as well as ecofriendly technologies in agriculture ensures food security and adaptation to cli­ mate change. The global trend from TE 1970 to TE 2020 indicated that the area under wheat has increased by 10%. Similarly, production (+142%) and productivity (+135%)

Wheat Production, Trade, Consumption, and Stocks

53

in wheat have also shown an increasing trend of more than twofold. Regional-level analysis shows that Asia and European countries are the largest contributors to global wheat production with a steady growth in the respective production levels. India occu­ pies the first position in terms of area, whereas China and New Zealand rank first in terms of production and productivity, respectively. Although the performance of wheat production among different countries is largely satisfactory, yet significant effi­ ciency gaps are observed among major wheat-producing regions. This necessitates specific research intervention for augmenting the productivity level and minimizing the yield gap as well as the realization of higher yield potential. Further, the global wheat export and import have also significantly increased and registered positive growth from TE 1970 to TE 2020. However, although Asia is a major wheat producer, it has not realized the full export potential compared to other regions. It is evident that wheat is a staple food for billions of households with all the required nutrients, and the wheat stock and consumption level have significantly increased all over the regions. To increase wheat production, attention needs to be given to the development of improved varieties which can withstand all situations and make it to reach the farm­ ers’ field through extensive outreach programs. Further, policies need to be developed and implemented like incentivizing farmers to promote the adoption of climate-smart farm practices to produce more wheat with fewer resources in the context of climate change. To gain maximum benefits from trade and to increase export competitiveness, domestic support should be given without distorting the trade. Finally, there is a need to develop a framework to create enabling environment for easy access to quality seeds (for producers), affordable nutri-rich cereals (for consumers through an efficient distribution system), investment in R&D (for researchers to realize the genetic gain), and infrastructure at all levels, which strengthens the complete value chain.

REFERENCES Breiman, A.,  & Graur, D. (1995). Wheat evolution. Indian Journal of Plant Sciences, 43(2), 85–98. Collins, S. (2007). Treating severe acute malnutrition seriously. Archives of Disease in Childhood, 92(5), 453–461. DES. (2022). Directorate of Economics and Statistics, Department of Agriculture and Farmers Welfare, Ministry of Agriculture and Farmers Welfare, Go vernment of India. https://eands.dacnet.nic.in/ Drewnowski, A., & Popkin, B.M. (2009). The nutrition transition: New trends in the global diet. Nutrition R eviews, 55, 31–43. https://doi.org/10.1111/j.1753-4887.1997.tb01593.x. Erenstein, O., Jaleta, M., Mottaleb, K.A., Sonder, K., Donovan, J., & Braun, H. (2022). Global trends in wheat production, consumption and trade. In M.P. Reynolds & H.-J. Braun (ed s.), Wheat Improvement, 47–68. https://doi.org/10.1007/978-3-030-90673-3_4. FAOSTAT. (2022). Food and Agriculture Organization of the United Nations. Rome. www.fao.org/faostat/en/ Hallaert, J.J., & Munro, L. (2009). Binding constraints to trade expansion: Aid for trade objectives and diagnostics tools. OECD Trade Policy Working Papers, No. 94, OECD Publishing, France. https://doi.org/10.1787/5kmlbl6glf5d-en Joshi, A.K., Mishra, B., & Chatrath, R. (2007). Wheat improvement in India: present sta­ tus, emerging challenges and future prosp ects. Euphytica, 157, 431–446. https://doi. org/10.1007/s10681-007-9385-7.

54

Wheat Science

Kandpal, A., Kumara, K., Sendhil, R.,  & Balaji, S.J. (2022). Technical efficiency in Indian wheat production: regional trends and way forward. In  New Horizons in Wheat and Barley Research, 475–490. Singapore: Springer. https://doi. org/10.1007/978-981-16-4134-3_17. Li, Y., Zhang, W., Ma, L., Wu, L., Shen, J., Davies, W.J., Oenema, O., Zhang, F., & Dou, Z. (2014). An analysis of China’s grain production: looking back and looking forward. Food and Energy Security, 3(1), 19–32. Lin, H.I., Yu, Y.Y., Wen, F.I.,  & Liu, P.T. (2022). Status of food security in East and Southeast Asia and challenges of climate change. Climate, 10, 40–49. https://doi. org/10.3390/cli10030040. Llanto, G.M. (2011). Binding constraints to regional cooperation and integration in South Asia. Asian Development Bank, Mandaluyong, Philippines. https://www.adb.org/ sites/default/files/linked-documents/rcs-south-asia-2011-2015-oth-03.pdf Nasurudeen, P., Kuruvila, Anil, Sendhil, R., & Chandrasekar, V. (2006). The dynamics and inequality of nutrient consumption in India. Indian Journal of Agricultural Economics, 61(3), 362–370. Nelson, J.H. (1985). Wheat: it’s processing and utilization. American Journal of Clinical Nutrition, 41(5), 1070–1076. Nigatu, G., & Motamed, M. (2015). Middle East and North Africa region: an important driver of world agricultural trade. A Report from the Economic Research Service, USDA, AES-88. www.ers.usda.gov Opine, O.O., Jideani, A.I.O., & Beswa, D. (2015). Composition and functionality of wheat bran and its application in some cereal food products. International Journal of Food Science and Technology, 50(12), 2509–2518. Posner, E.S. (2000). Wheat. In K. Kulp, G. Joseph, & J. Ponto (eds.), Handbook of Cereal Science and Technology. London: CRC Press. Ramadas, S., Kumar, T.K., & Singh, G.P. (2019). Wheat production in India: trends and prospects. In  Recent Advances in Grain Crops Research. London: IntechOpen. https://doi.org/10.5772/intechopen.86341. Rosegrant, M.W.,  & Agcaoili, M. (2010). Global Food Demand, Supply and Price Prospects to 2010. Washington, DC: International Food Policy Research Institute. Roy, J., & Banerjee, P. (2010). Connecting South Asia: The centrality of trade facilitation for regional economic integration. Promoting Economic Cooperation in South Asia: Beyond SAFTA, pp. 110–138. Saini, S., & Kozicka, M. (2014). Evolution and critique of buffer stocking policy of India (Working Paper 283). New Delhi: Indian Council for Research on International Economic Relations (ICRIER). Senapati, N.,  & Semenov, M.A. (2019). Assessing yield gap in high productive coun­ tries by designing wheat ideotypes. Sci Rep, 9(1), 5516. https://doi.org/10.1038/ s41598-019-40981-0. Sendhil, R., Kumara, T.M.K., Ramasundaram P., Sinha, M.,  & Kharkwal, S. (2020). Nutrition status in India: dynamics and determinants. Glo bal Food Security, 26, 100455. https://doi.org/10.1016/j.gfs.2020.100455. Sendhil, R., Kumari, B., Khandoker, S., Jalali, S., Acharya, K.K., Gopalreddy, K., Sign, G.P., & Joshi, A.K. (2022). Wheat in Asia: trends, challenges and research priorities. In New Horizons in Wheat and Barley Research, 33–61. Singapore: Springer. https:// doi.org/10.1007/978-981-16-4449-8_3. Sharma, I., Tyagi, B.S., Singh, G., Venkatesh, K.,  & Gupta, O.P. (2015). Enhancing wheat production – A global perspective. Indian Journal of Agricultural Sciences, 85(1), 3–13.

Wheat Production, Trade, Consumption, and Stocks

55

Sharma, P., Dwivedi, S.,  & Singh, D. (2016). Global poverty, hunger, and malnutri­ tion: A situational analysis. In U. Singh, C. Praharaj, S. Singh, & N. Singh (eds.), Biofortification of Food Crops. New Delhi: Springer. Shewry, P.R., & Hey, S.J. (2015). The contribution of wheat to human diet and health. Food and Energy Security, 4(3), 178–202. Singh, S., Chand, R., Sendhil, R., & Singh, R. (2017). Tracking the performance of Indian agriculture. Indian Journal of Agricultural Sciences, 87(12), 1619–1626. Sramkova, Z., Gregova, E., & Sturdik, E. (2009). Chemical composition and nutritional quality of wheat grain. Acta Chimica Slovaca, 2(1), 115–138. Svanidze, M., Götz, L., Djuric, I., & Glauben, T. (2019). Food security and the functioning of wheat markets in Eurasia: a comparative price transmission analysis for the coun­ tries of Central Asia and the South Caucasus . Food Security, 11, 733–752. https:// doi.org/10.1007/s12571-019-00933-y. USDA. (2022). United States Department of Agriculture. Washington, DC. https://www. fas.usda.gov/data/ Wang, F., He, Z., Sayre, K., Shengdong, L., Jisheng, S., Feng, B.,  & Kong, L. (2009). Wheat cropping systems and technologies in China. Field Crops Re search, 111(3), 181–188. https://doi.org/10.1016/j.fcr.2008.12.004. Wilson, J.S., Mann, C.L.,  & Otsuki, T. (2004). Assessing the potential benefit of trade facilitation: A  global perspective (Policy Research Working Paper no. 3224). Washington, DC: World Bank.

3 Pre- and Post-Harvest Management of Wheat for Improving the Productivity, Quality, and Resource Utilization Efficiency Neeraj Kumar, Ganesh Upadhyay, Krishna Bahadur Chhetri,

Harsha B. R., Gulshan Kumar Malik, Ravindra Kumar, Poonam Jasrotia,

Shiv Ram Samota, Nitesh Kumar, R. S. Chhokar and S. C. Gill

CONTENTS

3.1 3.2

3.3

Introduction...................................................................................................... 58

Pre-Harvest Management in Wheat................................................................. 59

3.2.1 Seasonal Pattern of Wheat .................................................................. 59

3.2.2 Selection of Suitable Cultivars ............................................................60

3.2.3 Land Preparation .................................................................................60

3.2.4 Sowing/Planting .................................................................................. 62

3.2.5 Nutrient Management.......................................................................... 63

3.2.5.1 Soil Testing ..........................................................................64

3.2.5.2 Source and Amount of Fertilizers .......................................64

3.2.5.3 Method of Application of Fertilizers ................................... 65

3.2.5.3.1 Fertigation ......................................................... 65

3.2.5.4 Time of Application ............................................................. 65

3.2.5.4.1 Leaf Colour Chart.............................................66

3.2.5.4.2 SPAD Metre ......................................................66

3.2.5.4.3 GreenSeeker......................................................66

3.2.6 Water Management.............................................................................. 67

3.2.6.1 Conjunctive Use of Water .................................................... 67

3.2.6.2 Methods to Reduce Water Losses........................................ 67

3.2.6.2.1 Furrow Irrigated Raised Bed System (FIRBS) ...... 68

3.2.6.2.2 Sprinkler Irrigation ........................................... 68

3.2.6.2.3 Surface Drip Irrigation ..................................... 68

3.2.6.2.4 Sub-Surface Drip Irrigation.............................. 69

3.2.7 Weed Management Strategies for Wheat Crop ................................... 69

3.2.7.1 Cultural Methods of Weed Management............................. 70

3.2.7.2 Mechanical Weed Management........................................... 71

3.2.7.3 Chemical Weed Control....................................................... 71

3.2.8 Disease Management........................................................................... 72

3.2.9 Harvesting and Threshing Management ............................................. 79

Post-Harvest Management of Wheat ...............................................................80

DOI: 10.1201/9781003307938-3

57

58

Wheat Science 3.3.1 3.3.2

Losses During Post Harvest ................................................................ 81

Grading................................................................................................ 82

3.3.2.1 Grade Specifications ............................................................ 82

3.3.3 Contaminants and Remedies............................................................... 82

3.3.4 Packaging ............................................................................................84

3.3.4.1 Method of Packing and Packaging Material .......................84

3.3.5 Storage and Transportation .................................................................84

3.3.5.1 Storage .................................................................................84

3.3.5.2 Storage Structures................................................................ 85

3.3.5.3 Storage Facility .................................................................... 85

3.3.6 Major Stored Grain Pests and Their Control Measures ...................... 86

3.3.6.1 Cultural Methods ................................................................. 86

3.3.6.2 Mechanical Methods............................................................ 88

3.3.6.3 Chemical Control Methods.................................................. 89

3.3.6.3.1 Surface Treatment ............................................. 89

3.3.6.3.2 Seed Treatment ................................................. 89

3.3.6.3.3 Fumigation ........................................................ 89

3.3.6.3.4 Less Harmful Insecticides ................................90

3.3.6.3.5 Biological Control Methods..............................90

3.3.7 Supply Chain of Wheat .......................................................................90

3.3.7.1 Processing and Value Addition............................................90

3.3.7.2 Transportation...................................................................... 91

3.3.8 Some of the Profitable Flour Mill Business Ideas............................... 91

3.3.9 Market Practices and Constraints........................................................ 92

3.3.10 Cost and Margin .................................................................................. 92

3.3.11 Information Technology Applications................................................. 93

3.3.12 Constraints in Wheat Supply Chain .................................................... 93

3.4 Conclusion........................................................................................................ 94

References.................................................................................................................. 94

3.1 Introduction Rice and wheat are the staple foods which hold the major share in Indian food basket. Presently, the production of rice and wheat in India is estimated to be 130.29 million and 106.84  million tonnes (Mt), respectively, which represent 41.26% and 33.84% share of these crops in total food grains production (DES, 2022). The provision of minimum support price, suitable agro-climatic conditions, and increased mechaniza­ tion have been the prime reasons for intensive cultivation of rice and wheat crops, especially in northern Indian plains. However, the intensive adoption of rice–wheat system, particularly in Punjab and Haryana states, caused a destructive effect on the soil quality, groundwater table, nutrient balance, and crop productivity in addition to the challenge of residue management (Chauhan et al., 2012; Bhatt et al., 2016; Kumar et  al., 2022, 2023). In fact, the critical window period of 20–25 days between the harvest of paddy and sowing of wheat crop, timely unavailability of suitable residuehandling machines, their high cost, and inaptness of rice residue as fodder have been the prime factors responsible for burning of rice residue as wheat sowing beyond 30th November in a year can reduce the wheat yield by 26.8 kg day−1 ha−1 (Tripathi et al.,

Pre- and Post-Harvest Management of Wheat

59

2005). The burning of rice residue has been associated with a destructive effect on natural resources, loss of soil microorganisms, reduced efficacy of certain herbicides, and loss of straw retained nutrients. The alternative crop production methods like direct drilling of wheat under residue-free or residue-covered conditions using zerotill drill or conservation agriculture (CA)-based machinery have gained attention due to their ability of timely seeding of crop and cost reduction on the elimination of seed­ bed preparation. Further, the integration of zero-tillage with surface retention of crop residue provides multifarious benefits on moisture conservation, weed suppression, reduced soil erosion, improved soil organic carbon, higher water-holding capacity, and reduced soil bulk density (Mondal et al., 2019; Kumar et al., 2020; Saurabh et al., 2021). Jat et al. (2019) found 36% increase in system productivity, 43% augmentation in net profit, and 31.2% rise in system protein yield along with improved soil quality and 33% savings of irrigation water under CA-based rice–wheat–mung bean system over conventional rice–wheat system. It is clear that recycling crop residue back to soil as surface mulch adds multiple benefits to natural resources as well as growers. However, crop residue also serves as food and shelter for many insect-pests, requir­ ing timely and adequate measures for their proper control, failing which a penalty on yield and grain quality may be observed. The yield losses in wheat due to animal pest, pathogens and viruses could be as more as 8.7, 15.6 and 2.5%, respectively, depend­ ing upon the severity (Oerke, 2006). Moreover, the options of weed control by tillage operation are left out under CA-based cultivation, and it requires proper weed-control strategies to realize the similar crop yield and proper grain quality as with conven­ tional tillage practice. The yield losses in wheat due to weeds can be as high as 80% depending upon weed infestation (Chhokar et al., 2012). The other management practices on nutrients, water, and harvesting and threshing also impart significant role in yield, wheat quality, and profitability (Sarkar et al., 2013). In fact, the adoption of recommended pre-harvest management practices is prerequisite to obtain healthy grains, making them suitable for further processing and value addi­ tion. Like pre-harvest, post-harvest management also plays a crucial role in post-harvest losses, supply chain, quality of wheat product, and overall profitability (Grover and Singh, 2013; Amentae et al., 2017). Kalsa et al. (2019) reported that loss due to insects in wheat stored in farmers’ storage can be as high as 14%. In India, inadequate manage­ ment of food grains causes post-harvest losses of 7–10% of total production from farm to market level and 4–5% loss at market and distribution levels (World Bank study, 1999). It can be understood that both pre- and post-harvest management practices have decisive roles in ensuring the supply of quality wheat product to the consumers. In this chapter, an attempt has been made to provide the highlights on pre- and post-harvest manage­ ment of wheat for improving productivity, quality, and resource utilization efficiency.

3.2 Pre-Harvest Management in Wheat 3.2.1 Seasonal Pattern of Wheat Wheat is a Rabi crop, and its growing span varies according to agro-climatic condi­ tions. The variation in agro-climatic conditions affects vegetative and reproductive time of wheat, which produces a significant effect on potential yield. The sowing and harvesting time of wheat in different zones are presented in Table 3.1.

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TABLE 3.1 Sowing and Harvesting Time of Wheat (Triticum aestivum) in Different Zones Zone

Jan

Feb Mar April May June July Aug Sep Oct

Nov

NWPZ# NEPZ$

(17-23 Dec) (05-11 Nov) (10-16 Dec) (01-07 Jan) (12-18 Nov) (10-16 Dec) (01-07 Jan) (12-18 Nov)

CZ^ PZ

Dec

(05-11 Nov) (26 Nov-02 Dec)

NHZ*

(03-09 Dec) (24-31 Dec) (05-11 Nov) (26 Nov-02 Dec)

**

(17-23 Dec) Timely Sowing

Late Sowing

Very Late Sowing

Harvesting

Northern Hills Zone, #North Western Plains Zone, $North Eastern Plains Zone, ^Central Zone, **Peninsular Zone

*

Notes: *Northern Hills Zone, #North Western Plain Zone, $North Eastern Plain Zone, ^Central Zone, **Peninsular Zone

3.2.2 Selection of Suitable Cultivars The selection of appropriate wheat cultivar according to sowing, irrigation, and cli­ matic conditions is a preliminary step to realize the higher grain yield. The cultivation of wheat cultivar in a different zone than recommended results in declined yield due to alteration in vegetative and reproductive period of wheat. The new high-yielding cultivars of wheat require additional fertilizer quantity above the recommended dose and spray of growth retardant for the maximization of the yield with reduced risk of lodging. The performance of a particular wheat cultivar is influenced by various pre­ harvest management practices, which also bridge the gap between actual and potential yield. The major pre-harvest management practices pertaining to wheat are discussed in the following sections.

3.2.3 Land Preparation The feasibility and judiciousness in crop production can be ensured with the increase in crop rotation intensities, timely preparation of seedbeds, decrease in drudgery, and effective utilization of various resource inputs and fuel expenditure through energyefficient machinery. The use of resource-saving machinery, for instance, laser land levellers, rotary tillage implements (rotavator, power harrow, and powered discs), and the combinations of active–passive and passive–passive configured implements, is very useful for the timely preparation of seedbed, reducing the harmful effects of multiple vehicular passes on soil structure and minimizing the fuel expenditure costs, thereby resulting in more profit to the farmers. The concept of properly matching the tractor horsepower with the implement size and operating it at the optimal setting aids in low­ ering the time, manpower, and fuel costs in comparison to the traditional practices of seedbed preparation (Alam, 2000; Mehta et al., 2011; Mrema et al., 2014; Petrov et al., 2020; Nataraj et al., 2021). Laser-guided land levelling is one such modern sustainable practice, which has made a remarkable contribution in conserving irrigation water. The traditional leveling implements leave some areas of the field with high elevation, causing these regions to suffer from water stress conditions, while some areas of the

Pre- and Post-Harvest Management of Wheat

61

field having low elevation undergo surplus water conditions. It causes the variability in water and nutrients applied to crops, resulting in uneven crop stand and yield. These problems can be addressed by the laser land leveler which removes the soil from areas having higher elevation and fills it in the area of lower elevation, thereby precisely leveling the farm within ±20  mm of average farm elevation. The adoption of laser land leveling helps in reducing irrigation water demand (20–30%), abiotic stresses, and energy inputs in addition to raising agricultural productivity (10–20%) and profitability (Jat et al., 2006; Kaur et al., 2012; Shahani et al., 2016). Chen et al. (2022) witnessed 23.2% higher yield of winter wheat along with 30–40% increase in net-return through an integrated approach of precision land leveling along with precision seeding over conventional farmers’ practice. Amidst climate change and declining resources, the adoption of laser land leveling followed by resource-conserving implements for seed­ bed preparation and sowing would be beneficial to farmers to reduce input costs and improve net-profitability. The PTO-operated rotary tillage machinery, for instance, rotavator/rotary tiller, power harrow (vertical axis), or powered-discs, are widely used by farmers through­ out the world as they enable fine soil pulverization and proper mixing of manures and fertilizers. Multiple tillage passes given in the traditional seedbed prepara­ tion, namely ploughing, disking, cultivating, and planking can be substituted by the reduced passes of rotary tillage implements (Marenya and du Plessis, 2006; Upadhyay and Raheman, 2020a; Balsari et al., 2021; Hensh et al., 2021). Rotavator is reviewed to be more fuel-efficient and time-saving in contrast to the passivetype machinery with the additional benefit of its ability to carry out the puddling operation in wetlands (Destain and Houmy, 1990; Prasad, 1996; Kankal et al., 2016; Choudhary et al., 2021). The PTO-operated disc-type implements outperform the passive disc-type implements with higher residue incorporating ability, pulverizing index, operating depth, and fuel-energy utilization along with less draft, slippage, and required field trips (Islam et  al., 1994; Nalavade et  al., 2010; Upadhyay and Raheman, 2018, 2019). Several scientists worked on the different configurations of active–passive and passive–passive tools/implements for seedbed preparation and found promising results (Sarkar et  al., 2021; Bovas et  al., 2022). Integrating at least two tillage operations together can lower the operating costs for seedbed preparation and saves time. As the combined or integrated machinery could establish seedbeds in less field trips, this would further assist in reducing the subsoil compaction issue caused by tractor–tire traffic. The passive–passive configurations outperform the traditional practices with respect to energy consumption, time, and operating costs (Watts and Patterson, 1984; Sahoo, 2005; Raheman and Roul, 2013; Alkhafaji, 2020). Moreover, with active–pas­ sive combinations, the negative draft generated by the powered tools/implements and tractor-engine power is efficiently utilized. These integrations are energy-efficient and demand fewer tillage field trips than traditional implements to attain the proper seedbed quality (Shinners et  al., 1990; Anpat and Raheman, 2017; Upadhyay and Raheman, 2018, Usaborisut and Prasertkan, 2019). Kailappan et al. (2001) reported cost savings of 44–55% and time-saving of 50–55% in preparing seedbeds with an integrated machinery. The active–passive combination machinery by Usaborisut and Prasertkan (2019) reduced the draft and energy demand of subsoiling by 4.4–11.3% and 10.5–15.3% compared to the subsoiler.

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3.2.4 Sowing/Planting In the Indian Indo-Gangetic Plains (IGP) region, the rice–wheat cropping system is extended over a wide region stretching from Punjab to West Bengal, and it has per­ formed a crucial part in the Indian food security. In IGP, rice is generally grown in the warm, humid season (May/June to October/November) and wheat in the cool, dry season (November/December to February/March) (Gupta, 2003). The time window between paddy harvesting and wheat sowing in northwest India is about 7 to 10 and 15 to 20 days for Basmati and coarse rice grain varieties, respectively (IARI, 2012; Lohan et al., 2018). Combine harvesters cut the paddy crop at a particular height over field surface, thus generating two distinctive crop residue components i.e. anchored stubble and heaps of loose straw. An immense load of loose straw about 7.5 tonnes per hectare is left on the surface. Due to lack of availability of effective machinery and techniques for crop residue handling and for establishing the subsequent crop, farm­ ers favour its in-situ burning on the farm. Furthermore, repeated puddling operations for the sowing of paddy crop result in the development of a sub-surface hardpan hav­ ing an increased penetration resistance and reduced hydraulic conductivity, which impede the transfer of water/air and further hamper the establishment of subsequent crop roots (Aggarwal et al., 1995; Hassan and Gregory, 1999; Timsina and Connor, 2001; Kukal and Aggarwal, 2003). Subsoil compaction reduced water and nutrients use efficiency of wheat followed after rice by 38% and 22%, respectively, resulting in reduced root length density chiefly because of a decrease in nutrient uptake (12 to 35% for nitrogen, 17 to 27% for phosphorous, and up to 24% for potassium) (Sur et al., 1980; Ishaq et al., 2001). Many scientists have examined the impact of late sowing on phenology and wheat crop production. Sowing in mid-to-late November results in lower wheat yield because of elevated temperatures at the time of the grain-filling phase. Timsina et al. (2008) reported that, in general, sowing wheat beyond 15 November in Punjab, India, reduces the grain yield between 0.25% to 0.75%, 0.5% to 1.0%, and 0.8% to 1.0% for varieties having yield estimation under 4 t ha−1, 4 to 6 t ha−1, and greater than 6 t ha−1, respectively. Singh et al. (2016) carried out a simulation study to analyse the effects of mulching and sowing date on wheat grain yield in clay-loam and sandy-loam soils at Ludhiana, Punjab. Their findings suggested that the optimal sowing date for wheat grain is affected by both soil type and the pres­ ence/absence of mulch. Further, the management of residue after rice harvest plays a prominent role in timely seeding of wheat. The simultaneous task of paddy straw handling and direct wheat seeding can address both challenges of residue manage­ ment and timely seeding. Roto seed drill is an important implement for an effective handling of paddy crop residues and timely seeding of wheat. Sharma et  al. (2008) and Dixit et  al. (2014) reported that the Roto seed drill is beneficial for sowing wheat after paddy harvesting saving time and fuel costs as compared to traditional operation. However, it operates successfully in fields free from loose straw and leaves only standing stubble or little quantity of loose straw. The necessity of partial elimination of loose straw from paddy farms before wheat sowing is the major constraint of this machine (Singh, 2016). In recent times, resource-conserving machines such as Turbo Happy Seeder (THS), super seeder, and strip-till drill have been used for residue management and timely seeding of wheat and other crops.

Pre- and Post-Harvest Management of Wheat

63

In THS, the cutting and shredding of straw are accomplished with inverted ‘γ’ type serrated flails fitted on a rotor (1,000 to 1,300 rev min−1) of the residue management drum. These flails shear standing stubbles near the ground and also throw the resi­ due over saw-edged blades fitted on the interior section of the management drum to achieve fine chopping and shredding. Sidhu et al. (2015) observed an improved yield of wheat sown in paddy stubble fields with the THS as compared to the conventional practice of straw burning followed by tillage and sowing operations. The use of THS also decreased fuel expenditure and ensured the optimum sowing window and reduc­ tion in the irrigation requirement. Despite the aforementioned merits, the farmer’s acceptance towards THS is slow. Sharma et al. (2008) and Chhokar et al. (2018) iden­ tified the inadequacy of THS in wet residue, more energy demand, less time avail­ ability, and incompatibility in direct seeding of wheat on sugarcane-trashed fields as the primary obstructions in its adoption under wheat–sugarcane cropping systems. Super Seeder is tillage-cum-sowing machinery equipped with a rotavator fitted with ‘LJF’ blades at the front, followed by sowing and compaction units at the rear. It simultaneously prepares the seedbed and sows the wheat crop. Additionally, it can be used in residue-covered field, thereby incorporating the crop residue into soil followed by seeding operation and compaction of the soil. The shape of ‘LJF’-type blades gives the benefit of gradual increment in bite-width as opposed to constant bite-width in traditional ‘L’-type blades during their impact on the ground. The ‘LJF’ blade shape lessens the chances of choking of blades with paddy straw and does its effective incorporation in the soil. But, for its efficient operation, tractors having engine power greater than 60 hp are required making it uneconomical for small and medium farm­ ers compared to the THS and strip-till drill. Strip-till drill is a tractor’s PTO-operated machinery for the direct sowing of various crops. It comprises ‘J’ type blades, which provide tillage in narrow strips required for proper seeds and soil contact and more favourable germination. It is an intermediate option between traditional and no-till practices and provides the advantage of improved seed germination as with normal tillage operation in direct seeding of crops without complete coverage of soil. Gangwar et al. (2006) witnessed a greater mean wheat yield with reduced (strip) tillage over conventional and zero tillage options under sandy loam soil. The strip-till drill permits the farmers for advanced sowing of wheat in paddy-harvested fields with comparable or greater yield as compared to traditional practice (Chaudhary and Singh 2002; Shukla et al., 2008; Hossain et al., 2012).

3.2.5 Nutrient Management In the past few decades, excessive or blind application of fertilizers has synced the food production with human consumption level, but it has depleted the resources and also caused the environmental problems. Over application of nutrients has increased the yield but with decreasing rate which has reduced the nutrient-use efficiency (NUE). Decrease in NUE has exploited the resources to the next level. Soil-testing­ based precise approach of nutrient application with the right amount at the right place in the right way at the right time is necessary to enhance NUE and yield of wheat. Quality of wheat can be increased by selecting a variety which is rich in qualitative parameters viz., protein and micronutrients (Fe and Zn). Supplying the deficient nutrients to the crops is also a prerequisite to overcome the problem of

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nutrient deficiency in the food chain at the human level. The nutrient management of wheat should be done by following steps for improving productivity, quality, and resource utilization efficiency.

3.2.5.1 Soil Testing It is the basic and primary requirement for proper application of fertilizers. Primary nutrients, viz., nitrogen, phosphorus and potassium, must be applied on the basis of soil testing. Other deficient nutrients could be applied either by soil testing analysis or based on visual plant deficiency symptoms.

3.2.5.2 Source and Amount of Fertilizers Nutrient-use efficiency of conventional fertilizers remains within 30–35%, 18–20%, and 35–40% for N, P, and K, respectively. So the use of slow-release fertilizers, smart fertilizers, nanofertilizers, and customized fertilizers could bring up the nutrient-use efficiency. Slow-release fertilizers like neem-coated urea have more NUE as they slowly release in the soil and meet the demand of crop for a longer period. Smart fertilizers have an emphasis on controlled-release systems to synchronize nutrient availability with the plant demands, thus reduce losses to the environment by enhancing the nutri­ ent-use efficiency. Nanofertilizers have a role in improving the nutrient-use efficiency by exploiting unique properties of nanoparticles within the range of nano-dimension from 1 to 100 nm. Customized fertilizers make it easier to apply a whole spectrum of required plant nutrients in the proper proportions for different stages of crop growth and development. Multi-nutrient carriers including macro, secondary, and/or micronutrients from both inorganic and organic sources are referred to as customized fertilizers. Other than recommended dose of fertilizer (150 kg nitrogen, 60 kg phosphorus, and 60 kg potassium per hectare) approach, soil test crop response (STCR) and nutrient expert approach can be used to calculate the required amount of fertilizers in wheat. This approach not only provides appropriate amount of fertilizers to the wheat but also gives the maximum yield (Table 3.2). TABLE 3.2 Different Tools for Real-Time Nitrogen Management in Wheat Effect on Grain Yield

References

30%

No significant difference

Reena et al. (2017)

42

18.8%

GreenSeeker

0.66

20%

Ghosh et al. (2020) Gupta (2006)

Soil test crop response (STCR) Nutrient expert (NE)

FN = 5.31 T − 0.51 SN (New Delhi) As per crop advisor (NE)

-

13.4% yield increment No significant difference -

16% yield increment

Pampolino et al. (2012)

Tools

Critical Values

% Saving of N

Leaf colour chart (LCC)

≤4

SPAD meter

-

AICRP on STCR

Pre- and Post-Harvest Management of Wheat

65

3.2.5.3 Method of Application of Fertilizers Nitrogen is the most limiting nutrient of the wheat. Whole nitrogen should not be applied as a basal dose because of its high mobility in the soil which makes it deficient in later stages. It should be applied in two to three splits. Nutrients, viz., P (essential for root development and tillering) and K (quality nutrient), should be applied as a basal dose as per the requirement of the crop based on soil testing. There is no need to sup­ ply sufficient nutrients like calcium, magnesium, and some micronutrients. Sulphur can be applied as basal dose and foliar spray if there is drop in N:S below 15–16:1. On the soil testing or deficiency symptoms of the crop, micronutrients can be applied either by mixing with macronutrients or by foliar spray.

3.2.5.3.1 Fertigation It is the process of the application of fertilizers with irrigation water, which allows for the application of small amounts of fertilizer per fertigation event, allowing for greater fertigation frequency flexibility. In fertigation, fertilizer solution is evenly distributed in irrigation. The availability of nutrients is abundant to the crop plants, so efficiency is increased. In fertigation, liquid and water-soluble fertilizers are used. Through fertigation, nutrients and water are delivered near the active root zone, resulting in a greater crop absorption. Because fertigation distributes water and fer­ tilizer evenly across all crops, an increase in 25–50% yield is possible. The fertil­ izer application through fertigation technique demonstrates 80–90% fertilizer use efficiency, resulting in the saving of more than 25% nutrients. Along with saving water and fertilizers, time, labour, and energy are all significantly reduced as a result of this method. In case of nitrogen fertigation, urea is an excellent choice for use in micro irrigation systems. It’s very soluble and dissolves in a non-ionic form, so it won’t react with other compounds in the water. Urea also has no effect on precipi­ tation. In drip fertigation, nitrogenous fertilizers such as urea, ammonium nitrate, ammonium sulphate, calcium ammonium sulphate, and calcium ammonium nitrate are employed. In P fertigation, phosphate salts may precipitate when phosphorus is added to irrigation water. Fertigation tends to be better with phosphoric acid and mono ammonium phosphate. Potash application through fertigation does not cause any kind of precipitation if used in the forms of KNO3, KCl, K 2SO4, and mono potas­ sium phosphate. Micronutrients, viz., Fe, Mn, Zn, Cu, B, and Mo, can also be used in drip fertigation.

3.2.5.4 Time of Application All primary nutrients which are required in higher quantities can be applied as basal dose except nitrogen. Though nitrogen, being the most limiting and highly mobile nutrient in the soil, is required appropriately at different growth stages of crop for maximizing the yield and enhancing its use efficiency, so, the most efficient use of nitrogen may be realized by matching N supply with crop need, which means applying the proper quantity of N at the optimal physiological stage of nutrient requirement. A potential approach is to use leaf colour chart (LCC), chlorophyll metre (or SPAD metre), GreenSeeker (NDVI meter), and others to assess the plant’s N demands and then adjust the time of N administration in wheat (Table 3.2).

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3.2.5.4.1 Leaf Colour Chart The leaf colour chart (LCC) is an inexpensive tool for determining the nitrogen demand of crop in real time. LCC indicates the nitrogen deficiency based on visual observation of differences in colour intensity of stripes and plant leaves. LCC contains six shades of green colour ranging from yellowish green to dark green. The LCC score increases with the intensification of green colour. If the mean score of at least six leaves falls below critical value (LCC of 4), a dose of 20–25 kg N ha−1 is applied. Then, LCC reading at 7 days’ interval is repeated till 50 days after transplanting. The application of nitrogen @50 kg ha−1 as basal and 30 kg ha−1 as top dressing in wheat with LCC reading less than 5 recorded 17.7 and 51.5% higher grain yield over recom­ mended dose of nitrogen (100 kg ha−1) and zero nitrogen, respectively (Dineshkumar et al., 2013). Singh et al. (2014) reported that LCC-based nitrogen fertilizer application produced equivalent or more grain yield than the blanket N recommendation with the average saving of 29 kg N ha−1 in wheat. LCC optimizes the nitrogen use in wheat with similar or high yield levels irrespective of the source of nitrogen (Parihar et al., 2018).

3.2.5.4.2 SPAD Metre The SPAD chlorophyll metre is excellent for quickly determining the chlorophyll con­ tent and nitrogen status of crops. Soil Plant Analysis Development (SPAD, Minolta Camera Co., Osaka, Japan) chlorophyll meter is a fast and non-destructive method which allows in-situ measurement of chlorophyll content (N status). SPAD meter mea­ sures the leaf colour as a representation for leaf N using green colour intensity as an indicator. The readings from SPAD are taken at 7- to 10-days intervals, starting from 21 days after sowing for wheat continues up to the first (10%) flowering. Readings should be taken on one point midway between the leaf base and tip. The readings thus obtained are utilized for nitrogen application on the basis of two approaches. 4. i. Sufficiency index approach: If the ratio of SPAD meter reading value in the question plot to well fertilized reference plot lies below 0.9, then the nitrogen is applied in the question plot (Hussain et al., 2000). ii. Threshold value approach: In this approach, a dose of nitrogen is applied when SPAD value falls below threshold value [critical SPAD value = 42 for wheat as suggested by Bijay-Singh et al. (2002)]. In a study, Bijay-Singh et  al. (2002) observed the maximum tillering and 20% higher wheat yield on applying 30 kg N ha−1 based on SPAD meter reading over con­ ventional practice. Khurana et al. (2008) used a critical SPAD value of 42 to show the significant gains in agronomic (63%) and apparent recovery (59%) in N efficiency as compared to farmers’ practice.

3.2.5.4.3 GreenSeeker GreenSeeker is a hand-held optical sensor which works on the basis of the reflectance of infrared light projected on a specified crop area of 0.61 m × 0.61 m when placed 0.6 to 1 meter above the target area (Bijay-Singh et  al., 2011). It is well correlated to leaf area index so it measures the photosynthetic efficiency of plants by sensing. The values of NDVI (normalised difference vegetation index) over crop canopy in

Pre- and Post-Harvest Management of Wheat

67

GreenSeeker range from 0 to +1.0. This tool is also used for real-time nitrogen appli­ cation in wheat. GreenSeeker-based strategy nitrogen fertilizer application in wheat saves 82% of nitrogen with statistically similar yield over farmers’ practice (Li et al., 2009). GreenSeeker-based strategy has achieved the highest agronomic efficiency 111% for winter wheat over other nitrogen management practices (Cao et al., 2017).

3.2.6 Water Management Being a Rabi season crop, wheat requires comparatively less water than the Kharif season cereals. The water requirement of wheat is 45–65  cm and varies depend­ ing on soil and climatic factors. The rainfall received during wheat growing period (long-term average = 12 cm) does not fulfill total water requirement of crops; hence, irrigation is necessary to fulfil the remaining needs of water (Singh et  al., 2016). Excessive and improper uses of water resources in the past decades have depleted the groundwater and other resources. There is a need of agronomic practices which will not only enhance the water-use efficiency of crop but also sustain the water resources from over-exploitation. These include conjunctive use of water, reduction of water losses through evapotranspiration (ET) and percolation, proper irrigation scheduling, use of efficient irrigation methods and weather-forecasting tools for proper water management.

3.2.6.1 Conjunctive Use of Water In some countries, there is scarcity of fresh water, so conjunctive use of saline water and fresh water with proper management practices enhances the water productivity without compromising the yield of wheat (Mojid and Hossain, 2013).

3.2.6.2 Methods to Reduce Water Losses In arid and semi-arid regions, water losses takes place mainly by two ways, viz., evapotranspiration (out of total evapotranspiration, transpiration causes 74 to 76%, while evaporation causes 24 to 26% loss as reported by Tfwala et al. (2021)) and perco­ lation (excessive application of water by traditional flooding in water-sufficient areas). Evapotranspiration losses could be minimized by using the water-use-efficient wheat variety and mulching. The selection of a high water-use-efficient variety could be helpful in proper utilization of water and also enhances the grain yield. Straw mulching, a possible practice with resource conservation tools, could provide many benefits to wheat by conserving soil moisture, maintaining soil temperature, enhanc­ ing nutrient status in soil, preventing soil and water loss, improving soil microbial activities, and also by reducing weed flora. Mulching of wheat boosts grain yield and water efficiency as compared to non-mulched wheat due to improved soil physical and chemical properties, as well as increased soil micro fauna activity by increasing soil moisture (Chen et al., 2015). Percolation loss is a result of flood irrigation which is a conventional method of irrigation. Flood irrigation method causes deep drainage below root zone causes water use inefficiency and temporary waterlogging leads to aeration stress in wheat (Kukal and Aggarwal, 2003). Excess water in the field leaches down the precious nutrients and bring anaerobic situation for a short period of time. To maximize water-use-efficiency,

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careful irrigation scheduling is necessary with appropriate amount of water, as flood irrigation reduces water use efficiency and sometimes productivity also (Qiu et al., 2008). The appropriate irrigation scheduling improves crop yield and water conser­ vation and helps in the consumption of applied inputs properly. The first approach relies on irrigating the crop at critical growth stages of crop, while second focuses on irrigating the crop on the basis of soil moisture depletion in the field, regardless of growth stages. Irrigation requirements varies from soil to soil which may be six to eight irrigations in sandy loam soil while three to four irrigations in heavy clay soil sown wheat (Kumar, 2009). The stages like crown root initiation (21–25 days after sowing), tillering (40–45 DAS), jointing (60–65 DAS), flowering (80–85 DAS), milking (105–110 DAS), and dough (120–125 DAS) are the critical growth stages for irrigation scheduling. Application of 45 mm of water rather than 60 mm at every stage could also save the irrigation water without any significant loss in wheat yield (Meena et al., 2019). Apart from the time of irrigation, the methods of irrigation application and crop cultivation also help in conserving the water along with improved yield. The cultivation methods like furrow irrigated raised bed system and micro-irrigation systems such as sprinkler and drip irrigation are beneficial for enhancing water-use efficiency and productivity of wheat as discussed later in the chapter.

3.2.6.2.1 Furrow Irrigated Raised Bed System (FIRBS) FIRBS method reduces seed and nitrogen requirements by 25% and irrigation water usage by up to 40%. Flood irrigation is avoided in this approach so the water is applied in the furrows which save water thus increasing the water-use efficiency, and fertilizer is applied exclusively to the raised beds.

3.2.6.2.2 Sprinkler Irrigation Flood irrigation generates uneven water distribution, water loss through seepage and deep percolation, excessive weed growth, salinization, and waterlogging, all of which have an impact on land and crop output. Sprinkler irrigation can achieve great irriga­ tion efficiency, which is not always attainable with surface irrigation systems. This approach has a high irrigation efficiency, making it suitable to hilly terrain and light soil, and can save up to 60% of water (Shankar et al., 2015). Liu et al. (2013) found that irrigating wheat through sprinkler method reduced evapotranspiration by 4 to 23% and recorded more crop water productivity (18–57%) and irrigation water productiv­ ity (21–81 %) over surface-irrigated wheat. Sprinkler also recorded 4.0 to 22.1% more dry matter accumulation over surface irrigation. Mini-sprinkler irrigation under zero tillage with residue saved 43.3 and 25.0% of water over surface-irrigated wheat under zero tillage with residue and conventional tillage without residue (farmers’ practice), respectively (Singh et  al., 2021). Mini-sprinkler irrigation under zero tillage also recorded similar yield with farmers’ practice.

3.2.6.2.3 Surface Drip Irrigation Drip irrigation, also known as trickle irrigation, is one of the most effective irrigation methods. It comprises a number of hollow plastic pipes of small diameter having emit­ ters or drippers on the surface through which water is dropped into soil at very slow rate (3–15 litres h−1). Drip irrigation has enhanced the yield and productivity of some crops (particularly spaced crops), labour and  cost savings, energy savings, less pumping

Pre- and Post-Harvest Management of Wheat

69

hours and therefore, simpler irrigation, better crop development, and improved soil health, in addition to water savings. Drip irrigation has more overall irrigation effi­ ciency (90–95%) than sprinkler irrigation (75%). Drip irrigation could save more than 20% of irrigation water as compared to surface-irrigated wheat (Kharrou et al., 2011). Chouhan et al. (2014) reported that drip-irrigated wheat recorded 12.14 and 21.76% more grain yield and water productivity than sprinkler-irrigated wheat, respectively.

3.2.6.2.4 Sub-Surface Drip Irrigation Sub-surface drip irrigation is the regular discharge of small amounts of water below the soil surface from discrete emission points or line sources. Sub-surface perforated pipes leak water as it flows by gravity, and irrigation water is delivered to the crops via soil capillary. Sub-surface drip irrigation minimizes evaporation losses, allowing bet­ ter water and nutrients’ application to the root zone, which leads to more enhanced fer­ tilizer and water-use efficiency, reduces weed growth, and lowers labour costs. It also makes cultural farming activities easier in sub-surface drip irrigation than in surface drip irrigation (Ayars et al., 1999). Due to lower evaporation losses, sub-surface drip irrigation has lowered ET by 26% compared to flood irrigation and 15% compared to surface drip irrigation, resulting in an increased grain yield and biomass (Umair et al., 2019). Sidhu et al. (2019) reported that use of irrigation water reduced by 42–53% in sub-surface drip irrigation (laterals spacing of 67.5 cm at 15-cm depth) under con­ servation agriculture based wheat cultivation as compared to a flood irrigation in the same crop establishment method. Sub-surface drip irrigation has improved crop and irrigation water productivity by 25 and 20% over flood irrigation, respectively. Other than time and application of irrigation, judicious and precise application of irrigation could be achieved by using weather-forecasting tools. By knowing upcoming rainfall, smart application of irrigation could be done which will not only save the water but also increase the grain yield by creating less waterlogged situations in the field.

3.2.7 Weed Management Strategies for Wheat Crop Among various pests, weeds are considered as major biotic limiting factor in crop pro­ duction. Weeds, besides reducing the yield and the quality of the produce, also hinder in harvesting operations. Globally, weeds cause about 18 to 29% yield reduction in wheat, subjected to weed population, type of weed flora, and its infestation duration (Oerke, 2006). Wheat, in general, is infested with both grass and broadleaved weeds. The most common and economically troublesome monocot and dicot weeds in wheatbased cropping systems include Phalaris spp., Avena spp., Lolium spp., Alopecurus spp., Bromus spp., Chenopodium album L, Raphanus raphanistrum L., and Kochia scoparia L. (Collavo et al., 2011; Chhokar et al., 2012). Weeds create competition for the resources, and the lodging nature of some weeds like Phalaris minor wanes yield as well as quality of wheat. Phalaris minor competes more fiercely for light because it has more and larger leaves than wheat (Malik and Singh, 1993). Lodging also creates difficulty in harvesting operations and lowers production and quality by shrivelling the grains. Mixing of weed seeds in wheat grains also decreases their export to foreign countries as a quarantine measure. Therefore, integrated weed management practices are essential for proper and timely control of weeds in wheat. The weed management approach is generally classified into three categories, viz., cultural, mechanical, and chemical weed control as discussed next.

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3.2.7.1 Cultural Methods of Weed Management In order to effectively manage the weeds in wheat, a multi-layered hierarchy of cul­ tural, mechanical, and chemical techniques is used. Different and frequently incon­ sistent methods of cultural weed management exist, which are detailed in Table 3.3.

TABLE 3.3 Effect of Different Cultural Practices on Weed Management Practice

Weeds Controlled

Stale seedbed technique

Most of weed flora

Details

Stale seed bed technique controlled 28.6% of weeds (Avena fatua, Phalaris minor, Chenopodium album) and enhance the wheat production by 5%. Zero tillage Phalaris minor Zero tillage practice reduced the P. minor by 40–45% and contributed to 25–30% in yield increment. Competitive A significant range of More competitive varieties having verities weed flora fast germination, more leaf area index, taller stature, improved root spread, and higher allelopathic effect suppress the weeds more efficiently. Sowing time Phalaris minor Early sowing of wheat reduced P. adjustments Avena ludoviciana minor by 15–20% and increased the grain yield by 10–15%, while late sowing reduced the infestation of Avena ludoviciana. Mulching Phalaris minor, Poa Mulching in wheat has potentially annua, Capsella reduced the weed population by bursa-pastoris, 38–80%, which contributed to Stellaria media yield increment by 12–32%. Crop rotation A significant range of A. fatua was significantly lowered weed flora, while shifting from rice–wheat Avena fatua L. cropping system (67%) to sugarcane–vegetables–wheat (9%) and cotton–pigeon pea–wheat (16%). Allelopathy Avena fatua L., Mulberry extracts resulted effect Phalaris minor in a complete inhibition of the wild oat and Phalaris minor germination. Irrigation time Chenopodium album L., Pre-sowing irrigation lowered the Chenopodium murale L. dry weight of Chenopodium album and Chenopodium murale by 21 and 25%, respectively. Fertilizer Avena fatua, Sonchus Low-nitrogen fertilized plots had management arvensis, less occurrence of weeds and Setaria viridis enhanced the grain yield by 10%. C. album

References Safdar et al. (2011)

Jabran and Farooq (2013), Blackshaw et al. (2002)

Singh et al. (1995, 1999)

Batish et al. (2007)

Malik and Singh (1995)

Jabran et al. (2010)

Singh and Singh (2004)

Blackshaw et al. (2004)

71

Pre- and Post-Harvest Management of Wheat

3.2.7.2 Mechanical Weed Management It consists of the uprooting and removal of weeds using a variety of tools and instru­ ments. Manual weeding requires a lot of manpower and time. Its profitability is very poor because labour is scarce and expensive. Moreover, weeds that morphologically resemble crops, such as P. minor and Avena ludoviciana before flowering, make mechanical weeding challenging. However, when wheat is seeded in FIRBS or in lines in a flatbed system, mechanical control can be used efficiently.

3.2.7.3 Chemical Weed Control Chemical weed control is recommended because it is more effective, less expensive, and takes less time. Additionally, it avoids the crop’s mechanical harm that results from mechanical weeding. Furthermore, the control is more effective because during mechanical control, the weeds that invariably escape due to morphological similarity to crop are killed even within the rows. Choosing the right herbicides for the type of weed flora that is infesting the crop and applying the herbicides at the right amount and timing are both essential for effective weed control (Table 3.4). However, the adoption of zero tillage agronomic practice and repeated dependence on the same group of her­ bicides for weed management evolved herbicide-resistant weeds in wheat. The report of herbicide-resistant weed species given in International Survey of Herbicide Resistant Weeds by Heap in 2022 ranked wheat first in the number of herbicide-resistant weed species (a total of 77 weed species herbicide-resistance cases globally). Dependency on new herbicides is also limited in some countries due to unawareness, government policies, and higher costs which divert out the focus towards integrated approach of weed management. Integrated weed management considers all relevant control TABLE 3.4 Different Wheat Herbicides, Their Optimum Doses, Time of Application, and Target Weeds Herbicide

Dose (a.i.) g ha−1

Grasses

Broad Leaf

Application Time

Clodinafop Fenoxaprop-ethyl Pinoxaden Sulfosulfuron Mesosulfuron + iodosulfuron Sulfosulfuron + metsulfuron Pyroxasulfone

60 100–120 35–40 25 12 + 2.4

√ √ √ √ √

√ √

Post-emergence Post-emergence Post-emergence Post-emergence Post-emergence

30 + 2

√

√

Post-emergence

127.5

√

√

1,500 25 (5 + 20)

√

√ √

Pre-emergence and early post-emergence Pre-emergence Post-emergence

Pendimethalin Metsulfuron + carfentrazone Metsulfuron 2,4-D

√ √

Post-emergence Post-emergence

4 500

Source: Chhokar et al. (2012)

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measures and methods available locally and should be opted for effective and eco­ friendly weed management in wheat. Integrated weed management approach in wheat is a multilayer hierarchy which includes cultural, mechanical, and chemical methods.

3.2.8 Disease Management Wheat crop is attacked by a number of diseases (Table 3.5) which significantly affect the crop performance. In Indian north-western plain zone, stripe rust or yellow rust (Puccinia striiformis f. sp. tritici), brown rust or leaf rust (Puccinia recondita), Karnal bunt (Tilletia indica), powdery mildew (Blumeria graminis f. sp. tritici), and loose smut (Ustilago segetum var. tritici) diseases are very important, while some diseases like FHB and powdery mildew are emerging in NWPZ of India. Symptoms-based TABLE 3.5 Some Diseases of Wheat Incited by Different Phytopathogens Crop

Type of Pathogens Disease Name

Wheat Fungi (Triticum aestivum L.)

Yellow rust or stripe rust Brown rust or leaf rust Black rust or stem rust Karnal bunt Loose smut Flag smut Spot blotch Septoria tritici blotch Septoria nodorum blotch Tan spot Powdery mildew Downy mildew (crazy top) Fusarium head blight Fusarium leaf blotch Wheat blast Alternaria leaf blight Common root rot

Bacteria

Nematode

Take-all Bacterial spike blight (gummosis) Basal glume rot and bacterial leaf blight Bacterial stripe (black chaff) Ear cockle

Causal Organism/Pathogen Puccinia striiformis f.sp. tritici Puccinia recondita Puccinia graminis f. sp. tritici Tilletia indica Ustilago segetum var. tritici Urocystis agropyri Bipolaris sorokiniana Zymoseptoria tritici (Septoria tritici) Parastagonospora nodorum Pyrenophora tritici-repentis Blumeria graminis f. sp. tritici Sclerophthora macrospora Fusarium graminearum Monographella nivalis (Anamorph Microdochium nivale) Magnaporthe oryzae pathotype Triticum Alternaria triticina Cochliobolus sativus, Fusarium spp., and Pythium spp. Gaeumannomyces graminis tritici Rathayibacter tritici; Clavibacter iranicus Pseudomonas syringae pv. atrofaciens; P. syringae pv. syringae Xanthomonas campestris (pv.) translucens Anguina tritici

Pre- and Post-Harvest Management of Wheat

73

diagnosis and management of these diseases are crucial to avoid significant yield losses in the crop and described next.

3.2.8.1 Stripe rust disease Stripe rust or yellow rust disease is the most serious economic concern for wheat as it can spike yield losses up to 100% in disease-inclined varieties (Chen, 2005). It is incited by Puccinia striiformis Westend. f. sp. tritici (Pst), the fungus pervasive in cool (10 to 16ºC temperature) and wet weather conditions (Chen et al., 2014). In India also, stripe rust is a major problem of wheat production especially in NWPZ. The symptoms of the disease appear as bright yellow-orange pustules or sori occur­ ring in stripes on the leaves producing yellow-orange uredospores (Figure 3.1a) that break through the epidermis, predominantly on the upper leaf surfaces (Prescott et al., 1986). The disease spreads from one season to another season through uredospores.

FIGURE 3.1 Some major diseases of wheat: (a) Stripe or yellow rust, (b) leaf rust, uredosori with ruptured host epidermis (inset), (c) Karnal bunt: infected ear, (d) disease grains, (e) loose smut, (f) fusarium head blight, (g) powdery mildew, and (h) spot blotch.

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3.2.8.2 Leaf rust disease Leaf rust or brown rust is incited by Puccinia triticina Eriks. (Pt), most frequent with vast spread among wheat rusts (Bolton et al., 2008; Huerta-Espino et al., 2011). The fungal incitant is prevalent in areas with mild temperatures (15–20°C) and moist con­ ditions (rain or dew). The disease manifests initially as very small, round, orange pus­ tules/sori, which are scattered over the leaves but scarcely on the leaf sheath and stem. These sori become brown with maturity (Figure 3.1b). Towards the end of the season, the telia may be formed in the same pustule. These telia are small, oval to linear, black, and covered by the epidermis. Severe incidence of leaf rust inflicts heavy yield losses. Management of stripe and leaf rusts: Cultural practices like timely sow­ ing help in avoiding the inoculum build up due to coinciding of conducive weather conditions and susceptible crop stages. Clean cultivation such as the removal of volunteer plants and alternate hosts is most recommended cultural practice to contain the pathogen (Figueroa et al., 2018). The use of genetic resistance is a traditional choice for rust management as toxicants’ application are expensive, weather-dependent, and raise environmental and health concerns (Figueroa et al., 2018). Recently developed resistant culti­ vars effective against stripe rust include DBW 327, DBW 332, DBW 303, WH 1270, DBW 187, HD 3226, WB 2, PBW 723, HPBW 01, DBW 88, HD 3086, DPW 621–50, PBW 752, DBW 90, DBW 296, HUW 838, HD 3298, HI 1621, HD 3271, PBW 757, DBW 173, WH 1124, etc. (for NWPZ) and HS 562, HS 542, HPW 349, HS 507, VL 907, VL 804, HPW 349, HS 507, VL 907, etc. (for NHZ). For leaf rust, DBW 327, DBW 332, WH 1270, DBW 187, DBW 222, HD 3226, PBW 723, DBW 88, HD 3086, DBW 90, HUW 838, HD 3298, HI 1621, HD 3271, HI 1636, GW 513, HI 1634, CG 1029, DBW 110, HI 1633, UAS 375, NIAW 317, HI 1605, HS 562, etc., cultivars may be deployed following zone-specific recommendation. Although resistancebreeding programme against rusts of wheat is very strong particularly in India (ICAR-IIWBR, 2021), the breakdown of resistance in newly bred culti­ vars opens the scope of use of safer fungicides (Figueroa et al., 2018). On the appearance of the rust diseases, foliar spray with 0.1% Propiconazole 25% EC or Tebuconazole 25.9% E.C. or Triadimefon 25% W.P is suggested. The spray may be repeated after 15–20 days’ interval, keeping disease severity and spread in mind (ICAR-IIWBR, 2021).

3.2.8.3 Karnal bunt The Karnal bunt (KB) of wheat was first reported by Mitra in 1930 from Regional Station of IARI at Karnal, Haryana (Mitra, 1931). This disease is caused by Neovossia indica (formerly Tilletia indica). Moderate temperatures (19–23 °C), high humidity (>70%), and cloudiness or rainfall during anthesis are favourable environmental con­ ditions for the disease development. It is very tough to diagnose the infection in field as only few kernels in an ear-head are infected, and maximum of the infected kernels do not exhibit symptoms before maturity. The disease produces a dark colour and a fishy smell on infected kernels. Usually, only the germ end of the kernel shows symptoms, but, occasionally, the entire kernel may appear diseased. The darkening of the kernel is a result of the kernel tissue being converted in a teliospore mass by the

Pre- and Post-Harvest Management of Wheat

75

fungus (Figure 3.1 c, d) (Gupta and Kumar, 2020). In severe cases, grain may appear as black shiny sack of teliospores. The embryo and endosperm are not colonized. The pericarp ruptures during threshing, and teliospores are deposited in soil and remain adhered to the surface of the seed. Management of Karnal bunt: The disease management can be categorized into the following two segments: Pre-harvest management strategies: Since the KB pathogen perpetuates through soil and seed, the adoption of disease-free seed for sowing and rotating the cycle with non-host crops can help in managing this disease (Bashyal et al., 2020). The resistant sources against Karnal bunt disease are scarce because KB resistance is polygenic and partially dominant (Bashyal et  al., 2020). The available resistant/tolerant varieties recommended for the particular zone should be employed to contain the disease. Biocontrol agents having antagonistic potential against this pathogen include Trichoderma viride, T. harzianum, and Gliocladium deliquescens (Bashyal et al., 2020). Out of the various fungicides assessed for foliar application, propiconazole (Tilt 250 EC) at the heading stage provided 71.4–100% disease control (Aujla et al., 1989; Singh et  al., 1989). Gupta et  al. (2020) found propiconazole effec­ tive with stage-specific applications combined with soil amendment with Trichoderma viride. Some other fungicides such as bitertanol (baycor), tebu­ conazole (folicur), and cyproconazole (SAN 619F) have also the potential for utilization at times of dire need (Bashyal et al., 2020). Postharvest management strategies: Post-harvest handling is very crucial to maintain seed quality. Poor handling may result in mechanical damage which is a major cause of seed deterioration, and it can facilitate the intro­ duction and easy establishment of pathogens, tending the seed prone to fungal invasion and limiting storage perspective (Shelar, 2008). Postharvest control of diseases employing mechanical processing is a very crucial and most reasonable newer method for attaining bunt-free grains/seeds in wheat since it is tough to detect the infection in the field, and KB-infected grain exhibits no symptoms before maturity. The seed/grain must be threshed and examined (Gupta and Kumar, 2020). Kumar et al. (2015) found that adjust­ ments in pre-cleaner and screen grader of the processing line assembly can eradicate up to 74.1% bunted seeds of the total KB-infected seeds present in the seed lot. They noticed that tip-infected seeds are hard to remove from healthy seeds as the density of such seeds remains at par with healthy seeds. Dayal et al. (2021) supported their study and improved seed quality in dif­ ferent wheat cultivars by reducing the Karnal-bunt-infected seeds through mechanical seed processing.

3.2.8.4 Loose smut disease This is an internal seed-borne disease, incited by a fungus Ustilago segetum var. trit­ ici (Kumar and Gupta, 2020). The disease symptoms appear post ear emergence. In this disease, complete inflorescence (except rachis) turns into black powdery mass of smut teliospores (Figure 3.1e). Initially, this powdery mass is covered with a delicate

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grey membrane which soon dissolves, and a large number of teliospores are released in the environment. Only the rachis remains intact on tillers, and the infected tillers may remain slightly shorter than healthy tillers (Bashyal et al., 2020). Wind and mod­ erate rain, as well as cool temperatures (16–22°C) are ideal for the disease spread. The teliospores from the infected ear-heads get dispersed by air to the open flowers of the healthy plants, and the disease cycle continues. Management of loose smut: The effective cultural practices include the use of disease-free seeds for sow­ ing. In case, the crop is being raised for seed production, proper monitor­ ing at the time of ear emergence is required. The infected tillers should be rouged out after covering them with long paper bags, and these infected tillers should be destroyed carefully (Kumar and Gupta, 2020). Hot water treatment by saturating the seed in cool normal water for 5–6 hours and then immersing it for 2 min in hot water at a temperature of 50°C followed by drying the seed eliminates the resting mycelium of Ustilago segetum tritici (Gupta and Kumar, 2020). Solar treatment of wheat seed includes the soak­ ing of the seed for 4  hours in cold water in the month of May–June and followed by sun drying in hot sunshiny days. After soaking, the mycelium in seed becomes active and get killed. Such seed fails to produce infected ears after sowing in the next crop seasons (Gupta and Kumar, 2020). The successful management of loose smut can be achieved efficiently by seed treatment with systemic fungicides like tebuconazole (Raxil 2 DS) at 1.5 g kg−1 of seed and carboxin (Vitavax) and carbendazim (Bavistin 50 WP) at 2.5 g/kg of seed. Bread wheat varieties like HS 277, VL 829, PBW 34, Halna and durum wheat varieties like PDW 233, WH 896, HI 8498 and RAJ 1555 can be employed as these cultivars have exhibited resistance against loose smut disease (Bashyal et al., 2020).

3.2.8.5 Fusarium head blight of wheat Wheat Fusarium head blight (FHB), which is also referred as wheat head scab or ear blight, is principally incited by Ascomycete fungus Fusarium graminearum (Figueroa et al., 2018). The initial symptoms manifest as minute water-soaked spots at the base or middle of glumes, rachis or on the first floret to flower which finally may result in premature senescence of the ear-head (Figure 3.1f). In warm and moist conditions, the pathogen sporulates as white-pink salmon mass on infected glumes and spikelets. Co-infections of various cereal-threatening Fusarium species including many locally unique species may lead to severe FHB epidemics (Brown and Proctor, 2013). Though FHB is the most serious and hazardous floral disease of wheat caus­ ing frequent epidemics in United States, China, the EU, the United Kingdom, Africa, Brazil, etc. (Figueroa et al., 2018), the disease is of minor importance in India, and this has been reported from some areas of Punjab and Himanchal Pradesh (Saharan et al., 2004; Teli et al., 2016). Frequent rains before and during the crop anthesis make the wheat prone against the FHB pathogen, and the prevalence of elevated temperature with the humid conditions during this crop growth stage favours the disease develop­ ment (Figueroa et al., 2018). The disease causes multifaceted impact on wheat: Yield and quality of grain; the accumulation of trichothecene mycotoxins (Teli et al., 2020);

Pre- and Post-Harvest Management of Wheat

77

and subsequently presenting health hazards to humans, cattle, poultry, and natural ecosystem (Figueroa et al., 2018). Management of FHB: The principle of field sanitation based upon tillage to bury infected crop residues to prevent the next generation of the fungal prop­ agules should be followed for reduction in disease incidence. Inclusion of non-host crops, for example, soybean, can help in disease management and reduction in deoxynivalenol (DON) accumulation (Dill-Macky and Jones, 2000). Disease-free seed should be used for sowing. The use of FHB-resistant cultivars is the most economical control measure (Wegulo et al., 2015) but is demonstrated to be slow and challenging to attain in elite wheats. FHB resistance is governed by multiple major and minor QTLs which are usually linked with a fitness cost or yield penalty (Gilbert and Haber, 2013). Fungicides are an important FHB disease-control measure. Seed treatment with Carboxin 75% WP or Carbendazim 50% WP @ 2.5 g kg−1 seed or Tebuconazole 2DS @1.25 g kg−1 seed is helpful in managing the disease. Though triazole (DMIs) mixtures sprayed during the optimum flowering stage could provide partial FHB control (McMullen et  al., 2012) due to intrinsic resistance of F. graminearum to triazoles. Unfavourable weather situations like rains reduce the efficacy of fungicides due to delayed sprays. Additionally, the use of single spray in managing the FHB in both the earlyand late-flowering tillers encounters certain technical hurdles (Figueroa et al., 2018).

3.2.8.6 Powdery mildew The disease remains prevalent in cooler areas. In India, it is found in hilly regions, foothills and plains of north-western India, and the southern hills (Nilgiris) (Kashyap et al., 2018). The disease symptoms manifest as superficial small patches of greyish white cottony growth on leaves, sheath, stem, and even on ear-heads (Figure 3.1g). The symptoms appear initially on upper surface of leaves and, later, on both surfaces. With an increase in disease severity, the white cottony growth can spread over entire leaf and other aerial parts of the host (Kashyap et al., 2018). At the later phase of the disease, cleistothecia are formed in late crop season, and colour of the patches turns into brownish to dull tan. Management of powdery mildew: The use of recommended seed rate is an important cultural practice as it helps to avoid dense plant stand, which favours the disease development. Deployment of disease-resistant/tolerant cultivars helps to manage the disease. On the appearance of the disease symptoms, triadimefon 25% WP @0.1% can help in disease management (Kashyap et al., 2018).

3.2.8.7 Spot Blotch Disease The fungal incitant of spot blotch, Bipolaris sorokiniana, can produce disease symp­ toms on all plant parts, viz., internodes, stem, nodes, leaves, awn, glumes, and seed. Damping off (pre- and post-emergence), foot rot, seedling blight, leaf spot, and spike

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Wheat Science

blight are main diseases which are caused by this pathogen at different growth stages of the wheat plant. In spot blotch, the successful interaction of susceptible host and a virulent Bipolaris sorokiniana results in the appearance of small pinheads like dark brown to blackish spots with or without yellowing around it. As the disease progresses, these spots enlarge in size (Figure 3.1h), and several lesions coalesce turning into big­ ger necrotic regions of up to several centimetres long. In the advanced stage of this disease, the symptoms may be visible on sheath, ear, and awns of the affected plants, and spikelet infection results in grain shrivelling and black point. Warm and humid climate favours the fast growth of pathogen, especially after anthesis in host plant. Management of spot blotch disease: Agronomic practices such as crop rota­ tion, balanced use of recommended fertilizers, clean cultivation, use of efficient biological control agents besides deployment of resistant/tolerant cultivars, and judicious fungicidal sprays serve as IDM practices for reduc­ ing the spot blotch disease levels (Singh et al., 1998). Early sowing of the wheat crop circumvents the coincidence of crop growth stage favourable for pathogen development under hot and humid period. Sources of resistance against Bipolaris sorokiniana are scanty among commercial wheat variet­ ies in India. Nevertheless, for an effective management of the disease, the cultivation of recommended (tolerant) varieties, like HI 1612, HD 3171, HD 2985, HI 1563, DBW 39, CBW 38, NW 1014, NW 2036, K 9107, HD 2733, DBW 14, HD 2888, K 0307, DBW 39, and HUW 468, should be encouraged (ICAR-IIWBR, 2021). Fungicides applied in seed treatments include captan, mancozeb, maneb, thiram, carboxin, iprodione, and triadimefon (Stack and McMullen, 1988; Mehta, 1993). Foliar sprays of triademinol, fentinaacetate, propiconazole, Dithane Z-78, iprodione, imazalil, and kresoxim-methyl pro­ vide efficacious check on the disease. Though the economic viability of these fungicides in managing high disease pressure under conducive environment may be an issue. Further, Singh et al. (2008) concluded that the foliar sprays with propiconazole at 0.1% (Tilt 25 EC) on first appearance of disease and later at 15-day intervals thrice were most effective in managing the inci­ dence of leaf blight complex incited by Bipolaris sorokiniana [Cochliobolus sativus] and Alternaria triticina). Kavita et  al. (2017) evaluated 15 fungi­ cides in vitro against B. sorokiniana of barley and found that propiconazole at 0.1% and 0.05% was the most effective in controlling mycelial growth of pathogen. Magar et al. (2020), checked in vitro efficacy of eight fungi­ cides against B. sorokiniana, using poisoned food technique. Among the fungicides evaluated, propiconazole 25% EC (Tilt) was most effective fun­ gicide which completely inhibited the mycelial growth (Magar et al., 2020). Whereas, Raj (2021) concluded that Tebuconazole 50% + Trifloxystrobin 25% WG (Nativo) and Propiconazole 25% EC (Zerox) at both 75 and 100 ppm were most effective in completely inhibiting the radial growth of patho­ gen among the tested seven fungicides. Several fungal biocontrol agents including Trichoderma viride, Trichoderma harzianum and Trichoderma virens, Trichoderma reesei, and Chaetomium globosum (Singh et al., 2018; Darshan et  al., 2020) exhibited strong antagonistic capacities against B. sorokiniana and demonstrated the potential to be utilized for the spot blotch disease management.

Pre- and Post-Harvest Management of Wheat

79

3.2.9 Harvesting and Threshing Management The time of harvesting and moisture content of the crop along with the harvesting technique used (i.e. manual or mechanical) are the crucial factors that decide the quality and yield of the crop. Early harvest at higher moisture increases drying costs, vulnerability to mould growth, and disease infestation and leads to more broken seeds (Khan and Khan, 2010; Benaseer et al., 2018). However, a delay in sowing the subsequent crop because of the scarcity of labours in the peak sea­ son, unforeseen natural calamities, and weather change are the obstructions in the timely harvesting of wheat crop and cause considerable loss to the farmers due to higher shattering losses. The losses could be as high as 2 to 7%, if there is a delay in the harvesting of wheat (Iqbal et al., 1980; Benaseer et al., 2018). The optimum moisture of the grain should be 18–23% at the time of harvest and 12–20% at the time of threshing. According to Ladha et al. (2007), approximately 25 to 50% of the grain value, which basically governs the market price, is lost due to poor schedul­ ing of harvesting and threshing operations, inefficient control of the grain moisture at different phases of processing, and poor handling and milling. Basavaraja et al. (2007) have estimated the storage losses in wheat to be about 33.5% of the total losses, while harvesting and threshing operations together contribute about 17% of total post-harvest losses. Grover and Singh (2013) found an increase in wheat harvesting losses from 1.5% to 2.5% due to high shattering losses when harvesting was delayed in Punjab, India. The advancement in mechanical harvesting techniques enables timely harvest of the crop. The mechanical harvesting techniques encompass (i) simultaneous harvest­ ing and threshing with self-propelling combines, (ii) reaping and windrowing with self-propelling/tractor-operated reapers, (iii) stripping of grains from standing crop with strippers, and (iv) mechanical reaping and binding with reaper-binders. Reapers enable harvesting of crops mostly at the ground level. The working capacity of reap­ ers may vary from 0.25 to 0.40 ha h−1 for operating width of 1.20–2.20 m (Murumkar et al., 2014; Nadeem et al., 2015). Parida (2008) witnessed the cost of operation and manpower requirement of harvesting by a tractor-mounted reaper as 63 and 25% of traditional harvesting with a sickle, respectively. Similarly, the cost of operation and manpower requirement of harvesting by a self-propelled reaper was found to be 51 and 26% of traditional harvesting, respectively. Kumar et al. (2019) also observed cost savings of 32.4% and a benefit–cost ratio of 2.08 during the harvesting of wheat crop with a reaper-binder machine having 1.22 m cutting width as compared to the manual harvest with labours. During the harvesting of a crop by combine harvesters, both the crop parame­ ters (type, variety, moisture content, grain–straw ratio, and lodging of the crop) and machine parameters (reel index, position of reel, height of cutter bar, forward speed, cylinder rpm, cylinder-concave clearance, blower rpm, and sieves’ size) affect the grain losses (Srivastava et al., 1990; Singh, 2016). Lashgari et al. (2008) found the values of cylinder speed 800 rpm, forward speed 1.8 km h−1, and concave clearance 25  mm to be the best setting for a combine harvester (John Deere 955) based on the wheat kernel breakage and seed germination parameters. Kumar et  al. (2017) reported less unthreshed grains percentage and kernel breakage with a decrease in operating speed from 4.05 to 3.25 km h−1 and an increase in crop moisture content from 16 to 20%. In another study, Sattar et  al. (2015) reported total grain losses

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Wheat Science

to be 4.28, 3.85, and 2.92% of the gross yield in manual harvesting and threshing, mechanical reaping and threshing, and combine harvesting operations, respectively. Pawar et al. (2008) found that the total field losses were lesser in wheat crop harvested with combine (4.20%) as compared to harvesting done with a self-propelled vertical conveyor reaper (VCR) and thresher (10.57%). It was found that the use of a combine harvester is more profitable in larger fields, whereas the combination of self-propel­ ling VCR and thresher is a better economical option in smaller farms. Ahuja et al. (2007) reported a 44.9% cost saving and 2.4% increase in the yield during the com­ bine harvesting of wheat crop as compared to manual harvesting followed by power threshing operation. Patel and Varshney (2014) found a forward velocity 1.5 km h−1 and crop moisture content 9.16% as the best suitable parameters for harvesting wheat crop with a plot combine harvester. For the threshing of wheat crop, spike tooth type threshing cylinders are generally preferred by the farmers due to their easy design, low price, less energy consump­ tion, and grain breakage along with their capability to produce good-quality bhusa. The requirement of good-quality wheat bhusa suitable for animal consumption led to constraints in the adoption of combine harvesters and the improvement in the design of power threshers that could effectively thresh the grains besides delivering 10 to 20 mm long wheat straw (Tiwari et al., 2019). As reported by Tiwari et al. (2018), the majority of wheat threshers in India have spike tooth-type cylinders powered with a 3–4 kW prime mover. The parameters such as feeding chute angle, spike tooth characteristics (shape, dimensions, and number), cylinder parameters (type, diameter, and speed), and concave parameters (shape, size, and clearance) affect threshing effi­ ciency and threshed grain’s quality. Tiwari and Chauhan (2018) reported that roundspiked cylinders having a tip diameter of 600  mm and thickness of 6  mm offered greatest threshing efficiency and good straw quality with least specific power con­ sumption and grain loss in the threshing of wheat crop. Multi-crop threshers based on the axial flow principle are also used for wheat, paddy, oilseed, and pulse crop threshing. These threshers have provisions for independent adjustments of the thresh­ ing cylinder and blower speeds to help in lowering the grain breakage and improving the cleaning efficiency. The fed crop advances spirally in-between the cylinder and concave for multiple rotations and gets threshed for a larger time by the repeated blows/impacts of the spike tooth (Khan, 1990; Harrison, 1991, 1992; Sessiz and Ülger, 2003). The CIAE multi-crop thresher suitable for both wheat and paddy con­ sists of a spiked cylinder, straw thrower, aspirator type blower, and cleaning sieves. For paddy crops, the spiral louvers provided in the semi-hexagonal top cover help to advance the crop axially from the feed side to the discharge side. The lengthy straw is thrown with the help of straw throwers. For other crops, the semi-hexagonal cover is substituted with a semi-circular cover, and a semi-circular disc is fitted between the cylinder and straw thrower. It helps to save 26–39% labour and time requirement along with 22% cost of operation compared to manual threshing operation (Pandey et al., 1997; Singh, 2016).

3.3 Post-Harvest Management of Wheat After successfully harvesting of the wheat, post-harvest losses may occur due to spill­ age, shattering or rodents, birds, insects, and damage during harvesting in field or

81

Pre- and Post-Harvest Management of Wheat

storage. Harvesting of wheat with high-moisture content attracts mould infestation. Post-harvest losses can be reduced using modern and available technologies.

3.3.1 Losses During Post Harvest The study estimates that around 8% post-harvest losses occur in wheat. Post-harvest losses in different activities are presented in Table  3.6. The adequate measures required to reduce the post-harvest losses of wheat are described here: • Ensure uniform drying of wet wheat grain soon after harvest. • Using suitable threshing and winnowing processes to avoid losses. • Use of effective methods to prevent grain contamination, as well as good storage and transportation packing. • Keeping the right amount of moisture in the air and using insect-control techniques before and during storage. • Providing aeration and moving stocked grains on a regular basis, as well as stirring grain bulk on occasion. • Modern transportation infrastructure to reduce losses on the farm and in the market. Further harvesting of wheat at proper time and moisture remains a prerequisite to diminish losses during post-harvest management activities. The following things should be adopted during the harvesting stage of wheat: • When the grains of wheat grow hard, the crop should be harvested. • Harvesting before maturity reduces grain recovery and increases the per­ centage of immature seeds, broken seeds, etc. • Harvesting delays result in grain breaking and spillage. Harvesting should be done during the dry summer season to avoid exposure to rodents, birds, and insect and pest infestation. Using the correct harvesting equip­ ment and methods, harvested wheat should be stored separately to avoid cross-pollination.

TABLE 3.6 Post-Harvest Losses of Wheat in Different Activities Sl. No.

Process

Losses during Different Processes (%)

1 2 3 4 5 6

Threshing Moisture Rodents Insects Birds Transport

1.0 0.5 2.5 3.0 0.5 0.5

Source: Report of the Committee on Post-Harvest Losses of Food grains in India, Ministry of Food and Agriculture, Govt. of India, 1971

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Wheat Science • Excessive drying and direct sun drying should not be done. • Proper threshing and winnowing must be carried out. To reduce losses during shipment, the grains must be packaged in clean and appropriate gunny bags.

3.3.2 Grading The bold-size grains of high quality attract higher prices. With greater purchasing power, quality products are in high demand. Heterogeneous quality is unavoidable because wheat is grown under a variety of agro-climatic settings. As a result, hav­ ing a single national language for defining quality features is required to ease sell­ ing without physical inspection. The following marketing advantages are provided by grading: • Low transportation and storage costs, as well as the knowledge of current prices and the right markets • Financial aid is simple, and future trading is simple. • Increases the market share. • High-quality products are available to consumers at affordable price. • Encourages competition.

3.3.2.1 Grade Specifications Depending on the end usage, different authorities grade it according to different criteria. The majority of the commodity may be classed as hard, semi-hard, or soft on the basis of kernel texture with their colour as white, amber, or red. Physical characteristics such as impurity or refraction, as well as the grain’s overall look, are mostly considered by Indian merchants. The various grading equipment used are as follows: • • • • • • • • • •

Wheat sample – 50 grams Sample divider by sampler – Tube or scoop Machine for cleaning and grading Plant for dust collection Air separation using screens Clean – graders De stoners Gravity separators Silo storage system and pre-cleaning CFTRI – Afflation detection kit

3.3.3 Contaminants and Remedies Soil, water, equipment and storage structures and materials are all sources of grain contamination. To reduce the contamination, all precautions including proper aeration

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should be taken. The adulterants in wheat grains produce negative impact on con­ sumer’s health (Table 3.7). Aflatoxin, a class of mycotoxins produced by fungi, can be contaminated in wheat grains during any process ranging from the field to storage, as long as the conditions are favourable for fungus growth. Some methods to control aflatoxins are described here: • Wheat should be stored in a moisture-free, dry, secure location. • It should be ensured that grains are properly dried to prevent the formation of fungus. • A scientific and proper storing method should be used. • By using a preventive/curative chemical treatment, one can avoid insect infestation and fungus contamination. • Grain that has been infested should be segregated. The adulterants in wheat grains can be examined by visual and other specific tests as presented in Table 3.8.

TABLE 3.7 Health Effects Associated With Different Adulterants in Wheat Grains Sl. No.

Adulterant Type

Health Hazards

1

Admixtures: Soil, mud, stones, foreign matters Chemicals: Residues such as zinc, mercury, tin, copper and others as well as pesticide residues above the prescribed limit Fungal: Salmonella toxins, stem rust, fusarium, loose smut, aspergillus hill bunt, etc. Viral: Machupo virus (rodent urine) Natural

Abrasive impact in the gastrointestinal tract

2

3

4 5

May cause damage to the liver and carcinogenic metal toxicity, as well as paralysis Vomiting, diarrhoea, paralysis, muscular weakness, liver, kidney, and brain damage Black typhus or Ordog fever Affects organs

Source: https://agmarknet.gov.in/Others/profile_wheat.pdf

TABLE 3.8 Some Simple Tests for the Detection of Wheat Adulterants SI. No.

Common Adulterants

Detection Technique

1 2

Soil, stone, grit in grains Hidden insect infestation in grains

Using grading tools and ocular inspection. Filter paper should be folded first. Then grains with the help of a hammer must be crushed after putting some grains on Ninhydrin (1% in alcohol)-soaked filter paper. A bluish purple patch denotes the presence of a hidden insect infestation.

Source: https://agmarknet.gov.in/Others/profile_wheat.pdf

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3.3.4 Packaging Food packaging is an important step in ensuring a longer shelf life and maintain­ ing product quality, as well as providing protection against degradation and damage during transportation and storage. Labelling and branding are inextricably linked to packaging. Consumers nowadays demand products in unit bundles. Therefore, the availability of good, sanitized, unadulterated food items is important. Wheat must be packaged with greater care for export. In today’s consumerist society, the box not only protects the contents but also draws the customer. The following features must be included in good packaging: • • • • •

It must keep wheat in good condition over a longer duration. It must be clean and easy to handle and transport. It must be recognizable and appealing to customers. It must be able to withstand spoilage. It must contain relevant information as per the norms.

3.3.4.1 Method of Packing and Packaging Material To pack the graded wheat, one should use new, dry jute bags or any suitable packaging materials as per the norms laid by concern authority. The insects, fungal infestation, or objectionable odour should not be there in the containers. Each package should be firmly sealed. Each shipment should only contain one type of wheat.

3.3.5 Storage and Transportation 3.3.5.1 Storage Wheat is the main staple meal for the bulk of the population, therefore it must be stored safely. The shrinking of land holding combined with the rapid increase in population necessitates the development of better storage facilities in order to minimize losses. Furthermore, by extending the marketing period, storage allows for greater price real­ ization. Factors impacting wheat quality during storage and transportation are: • • • • • • • •

Temperature Moisture and humidity Rodents and insects Grain quality prior to storage Storage structure used Sanitation and fumigants used Damage to the grain prior to storage Ambient factors, etc.

Harvested grains typically have a moisture level of 20%, but a moisture percentage of roughly 12% is recommended for storage. Natural or mechanical resources are used to dry the material. Wheat that has a moisture level of more than 13% at temperatures of 30 to 40°C is sensitive to moulds, which cause musty odours, discoloration, and

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reduced flour output. At 70% relative humidity, wheat has an equilibrium moisture content of 13.5% (relative humidity). A moisture content of 13 to 14% is appropriate for short-term storage, but 11 to 12% is recommended for longer-term storage of up to five years (Dixit et al., 2015).

3.3.5.2 Storage Structures Food grains are stored in villages in traditional buildings of various shapes and sizes with varying capacities. a) Underground storage structures: In states of Bihar, Karnataka, Maharashtra, Andhra Pradesh, and Madhya Pradesh, underground storage is popular particularly in dry portions. Although the lack of oxygen in underground storage buildings reduces infestation, moisture seepage can lead to mould growth and grain damage from rodents. b) Aboveground storage structures: There are two types of storage structures, viz. indoor and outdoor. These are categorized into: (i) Conventional storage structures such as mud bins, gunny jute bags, bamboo-reed bins, and metal drums. (ii) Better storage structures such as enhanced bins, silos, brick-built godowns, and cover and plinth (CAP) storage.

3.3.5.3 Storage Facility (i) Farmers/producers’ storage facilities: The wheat grain should be cleaned as much as possible before storing it, according to the code of practices pre­ scribed at the farmer level. The grain should be dried until the moisture con­ tent is below 12 to 14% depending on the storage period. Before filling the grain, cleaning and disinfecting the storage structure should be done. During filling of grains in the structure, the grains should be stirred with a large stick for proper settling. Before sealing the structure’s cover, pesticides should be applied in the required dosages to the grain. The inlet and outlet lids should be closed as soon as possible. Mud or other binding materials to gaps and crev­ ices should be applied as needed. Weevils and bugs would be unable to access the grain or structure and cause damage. To deter rats, the area around the structure must be cleansed. Also, spilled grain should be cleaned up around the structure. After emptying, proper cleaning and disinfecting of the building should be done. When it comes to the usage of chemicals and enhanced grain storage procedures, it is always a good idea to speak with local officials. (ii) Rural and mandi godowns: Farmers in rural areas keep their produce in their own houses or in various facilities. It is well known that farmers of marginal and small land holdings are unable to afford the modern storage structures to keep their produce until market prices are favourable for selling. Rural godowns are promoted by the government. Farmers bring their harvest to the mandi after the harvesting of crop. It is carried in bulk in bags com­ monly for storage or during the conveyance. This storage facility needs to be strengthened in order to accommodate proper storage and reduce losses.

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(iii) CWC, SWC, and FCI warehouses: (a) Central Warehousing Corporation (CWC) – In 1957, the CWC was founded as largest public warehousing company. Food grains, fertilis­ ers, and other items are stored in the godowns. (b) State Warehousing Corporation (SWC) – Each state has established its own warehouse. The SWC’s primary operating area is in the state’s dis­ trict locations. (c) Food Corporation of India (FCI) – FCI has a large storage capacity for food grains and plays an important role in Public Distribution System under National Food Security Act.

3.3.6 Major Stored Grain Pests and Their Control Measures Insects have long been associated with humankind, causing significant food losses by feeding on grains, contaminating foodstuff with their urine, hairs, and excreta; leav­ ing behind skin casts; creating disease issues, etc. (Gupta et al., 2022). The problem of insect pests in destroying food is particularly more under storage conditions, and this is because of the abundance of food provided by bulk storage, reduced movement of insects in search of food, and protection from the extreme of climate instability. (Walter et  al., 2016; Singano et  al., 2019). The presence of insects in storage com­ promises with both quality and the marketing value of grain (Ogendo et al., 2004), and, in some countries like Britain, the grain is being discarded even when there are just minor insect pest infestations. About 10% of the total production of food grains in India is lost due to post-harvest losses brought on by unscientific storage, insects, rodents, microbes, etc. (Kumar, 2017). According to reports, around 500 species of insects have been found to be associated with stored grain products. Among these, about 100 species of insect pests of stored products cause economic losses. Grains crops which suffer from insect damage during storage include cereals (rice, wheat, maize, etc.); pulses (chickpea, mung beans, black gram, green gram, cowpea, etc.); and oil seeds (soyabean, sunflower, linseed, etc.). Stored grain insect pests can be categorised into two groups, viz. primary and secondary pests. Primary pests are those which cause damage to whole grains, while secondary pests damage broken or already damaged grains. Based on where they attack, primary pests are further classi­ fied as internal and external feeders. The primary and secondary storage insect pests of stored grain are presented in Tables 3.9 and 3.10, respectively.

3.3.6.1 Cultural Methods (i) Sanitation: Cleaning and maintaining the storage structure properly on a regular basis are essential for preventing insect pest infestations (Kerstin and Charity, 2011; Mobolade et  al., 2019). Before harvest, all grain-han­ dling equipment is maintained and repaired, weeds are removed from around the bins, and major good hygiene steps like cleaning harvest and transportation equipment are taken. In addition, advanced protective mea­ sures including floor treatment with residual insecticide can be done, four to six weeks prior to harvest. In turn, this will eradicate those insects that were not removed during cleaning and migrated into the bin. The top four storage

87

Pre- and Post-Harvest Management of Wheat TABLE 3.9 Primary Storage Insect Pests of Stored Grain Common Name Rice weevil

Lesser grain borer Angoumois grain moth Pulse beetle

Drug store beetle Tamarind/peanut beetle Sweet potato weevil Potato tuber moth Areca nut beetle External feeders Red flour beetle Khapra beetle Indian meal moth Fig moth or almond moth Rice moth

Scientific Name Internal feeders Sitophilus oryzae, S. zeamais, S. granarius Rhyzopertha dominica Sitotroga cerealella Callosobruchus chinensis, C. maculatus Stegobium paniceum Pachymeres gonagra Cylas formicarius Phthorimaea operculella Araecerus fasciculatus

Family

Order

Curculionidae

Coleoptera

Bostrichidae Gelechiidae Bruchidae

Coleoptera Lepidoptera Coleoptera

Anobiidae Bruchidae Apionidae Gelechiidae

Coleoptera Coleoptera Coleoptera Lepidoptera

Anthribidae

Coleoptera

Tribolium castaneum, Tribolium confusum Trogoderma granarium Plodia interpunctella Ephestia cautella

Tenebrionidae

Coleoptera

Dermestidae Phycitidae Phycitidae

Coleoptera Lepidoptera Lepidoptera

Corcyra cephalonica

Galleriidae

Lepidoptera

TABLE 3.10 Secondary Storage Insect Pests of Stored Grain Common Name

Scientific Name

Family

Order

Saw-toothed grain beetle Long-headed flour beetle Flat grain beetle Grain lice

Oryzaephilus surinamensis Latheticus oryzae

Silvanidae

Coleoptera

Tenebrionidae

Coleoptera

Cryptolestus minutas Liposcelis divinitorius

Cucujidae Liposcelidae

Coleoptera Psocoptera

insects whose control decreased by 9–34-folds under poorer sanitation con­ ditions include C. ferrugineus, P. truncatus, C. cautella, and R. dominica (Morrison et al., 2019). (ii) Solar drying: Sun drying is the most well-known practice followed before the storage of any food grains started (Belmain and Stevenson, 2001). This procedure limits the storage misfortunes by moulds, staining, respiration, and insect attack. A  legitimate grain cleaning before storage guarantees

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uniform air circulation inside the storage structure. Air circulation assists with lessening the chances of the development of contagious fungal growth. In particular, the cleaning of grains upgrades the viability of the manage­ ment tactics like fumigation. Moumouni et al. (2014) reported that the solar drying of cowpeas at temperatures between 16.7 and 37.8° was an efficient way to minimize the damage of C. maculatus during storage. (iii) Frequent monitoring: Regular monitoring of stored grains conditions is necessary in order to detect any potential issues associated with storage moisture, temperature, and pest infestation. Smaller size of insects acts as a limiting factor, and it often becomes difficult or ineffective to identify pest range, unless frequent monitoring is taken into account. For the identifica­ tion and monitoring of stored grain insect pests, traps baited with synthetic aggregation pheromones have been designed. Pheromone-baited traps are the best monitoring devices in developing nations due to their low cost and species specificity.

3.3.6.2 Mechanical Methods (i) Hermetic technology: Hermetic technology has received a lot of support for the long-duration storage of grains (Likhayo et al., 2016; Baoua et al., 2016; García-Lara et  al., 2020). It involves reducing the use of refriger­ ation for pest control and food protection without the use of synthetic chemicals. It operates on the principle of deoxygenation. As a result, the respiratory systems of insects and the grain itself increase carbon dioxide levels and decrease oxygen levels to the point where aerobic respiration of pests is minimised. Airtight storage containers like super grain bags made from polyethylene and metal silos can help farmers to reduce post-harvest losses (Kumar and Kalita, 2017). De Groote et  al. (2013) proposed that larger grain borer  (Prostephanus truncatus) can be controlled  without insecticides by using hermetic storage, in the form of either metal silos or super bags. (ii) Monitoring technologies: Stored grain insect damage can be minimized only if the infestation is early detected followed by the implementation of appropriate control measures. Various techniques are being used for the detection and decision-making in storage pest management such as grain probe traps, sticky traps; pheromones light traps and visual lures, berlese funnel and acoustical methods, electrical conductance, machine vision, detection of parasitized stored products, diagnosis of early grain spoilage sensing technology, environmental sensing, acoustic sensing, image sensing, ionizing irradiation, and ozonation. (iii) Nanotechnology: The use of nanotechnology offers a significant potential for the management of insect pests and pathogens, particularly in stored grains, by delivering pesticides in a targeted and controlled manner (Gharsan et al., 2022). A nanosystem unit consists of two core components: an active ingre­ dient and a carrier. In addition to it, based on their chemical composition, nanoformulations can also be categorised into three main groups including (i) inorganic-based, solid, and non-biodegradable nanoparticles (gold, silver,

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copper, iron, and silica-based nanoparticles), (ii) organic-based biodegrad­ able nanoparticles (liposomes, solid lipid, and polymeric nanoparticles), and (iii) hybrid (combination of both inorganic and organic components) nanoparticles. For instance the plant-mediated green silver nanoparticles using plant Euphorbia prostrata (Zahir et al., 2012) and Avicennia marina (Sankar and Abideen, 2015) resulted in higher mortality of S. oryzae fol­ lowed by T. castaneum and R. dominica. Furthermore, guidelines for the discharge of nanomaterials were framed by the Australian Pesticides and Veterinary Medicines Authority (APVMA) (Bowman and Hodge, 2009; Walker et  al., 2017). Due to the widespread use of nanopesticide formu­ lations, there is also rising concern in the scientific community regarding their toxicity and effects on the ecosystem, which calls for additional study and research in these areas (Jasrotia et  al., 2022). In light of this, addi­ tional efforts are needed for the development of safer and more efficient nanoformulations.

3.3.6.3 Chemical Control Methods Most of the non-chemical techniques may not provide satisfactory results in insect management when used as sole method or in combination. Thus, in order to get satis­ factory results, the use of chemicals has become necessary.

3.3.6.3.1 Surface Treatment New gunny bags or clean old ones should be used by dipping them in 0.0125% Fenvalerate 20 EC or cypermethrin 25 EC for 10 min before filling them with grains. Malathion emulsion (0.05%) should be sprayed over the floor, walls, and ceiling of empty godowns or containers to disinfect them.

3.3.6.3.2 Seed Treatment Mixing of malathion 5% @ 250 g per quintal of seed is recommended. Alternatively, by dilution in 500 ml of water, the grains may also be treated with 1.5 ml of cypermethrin 25 EC or 25 ml of malathion 50 EC or 2 ml of Fenvalerate 20 EC or 14 ml of deltame­ thrin 2.8 EC per quintal of seed. To protect pulses from pulse beetle attack, covering the pulses stored in bulk with 7 cm layer of sand or sawdust or dung ash is suggested.

3.3.6.3.3 Fumigation Small quantities of grain can be disinfected using metallic drums or wooden boxes. In India, ethylene dichloride and carbon tetrachloride mixture have been advised for the fumigation of food grains in storage at the farm level (Mohapatra et al., 2015), and hydrogen phosphide in the form of aluminium phosphide or methyl bromide for protection in warehouses, godowns, and silos. Use of ethylene dichloride and carbon tetrachloride mixture with an exposure time of 4 days, at the pace of 1 litre for 20 quintals of grain or 35 litres per 100 m3, is recommended. Methyl bromide is utilized at a rate of 3.5 kg per 100 m3 of room with 10–12 hours of exposure. The fumigant, hydrogen phosphide (aluminium phosphide), is available in tablet form and can be used at the rate of one tablet (3 g) per metric tonne or 25 tablets per 100 m3 of space with an exposure period of 7 days. For instance Rajendran and Sriranjini (2008) proposed

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that the use of essential oils (mainly belonging to Apiaceae,  Lamiaceae,  Lauracea e, and Myrtaceae) and their components (cyanohydrins, monoterpenoids, sulphur compounds,  thiocyanates,  and others) along with CO2  or ethyl formate effectively control beetle pests such as Tribolium castaneum, Rhyzopertha dominica, Sitophilus oryzae and Sitophilus zeamais via fumigant toxicity.

3.3.6.3.4 Less Harmful Insecticides Numerous stored-grain-pests have evolved resistance against commonly used insec­ ticides. Resistance in Rhyzopertha dominica, T. castaneum, and Sitophilus oryzae against phosphine and Tribolium castaneum against lindane and malathion are some of the known cases. On the other hand, many active, less toxic chemical products are currently available for stored product usage, and their use may increase soon in near future. These includes harmless juvenile hormone analogs, diatomaceous earth, and spinosyns (Gupta et al., 2022). Research studies are being conducted to determine the efficacy of insect growth regulator (novaluron), a novel spinosyn (spinetoram), and neo­ nicotinoids (imidacloprid and thiamethoxam) for the management of stored grain pests.

3.3.6.3.5 Biological Control Methods There is a long list of biocontrol agents enlisted in various insect families such as Braconidae, Ichneumonidae, and Bethylidae against insect pests of stored commodi­ ties. The typical examples of biological control agents that have been used for stored insects include anthocorid bug, Xylocoris flavipes (Reuter) for the control of stored commodities pests such as Tribolium castaneum and T. confusum (Rahman et  al., 2009) and the use of egg parasitoid Trichogramma pretiosum in peanut warehouses for the suppression of Indian meal moth and so on.

3.3.7 Supply Chain of Wheat 3.3.7.1 Processing and Value Addition Processing of wheat enhances the value and also lowers storage and handling expenses. Wheat flour is manufactured in 5 to 10 hp burr mills, while suji and maida and by-products of 13% bran and 3% germ are produced in roller mills. The different processes involved in wheat milling are shown in Figure 3.2. The following steps are involved in wheat milling: Cleaning: The cleaning process involves the removal of contaminants and for­ eign materials, which hamper quality of wheat and rinsing thereafter. Conditioning: To maintain the gluten quality, the temperature of wheat is main­ tained below or at 47°C. Because both moistening and heating are done at the same time, hydrothermal treatment is employed for conditioning.

FIGURE 3.2 Different processes involved in wheat milling.

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Grinding: Roller mills, reduction roll systems, and scratch systems in general perform this task. Packaging: The finished goods are sealed in waterproof bags. They should be stored in a dry and cool environment. Blending: Due to an increase in health consciousness among customers, some flours are being blended, such as soybean flour, and flour is being fortified with riboflavin, vitamins A and D, and thiamine.

3.3.7.2 Transportation The mode and cost of transportation play a crucial impact in the transportation of wheat. The transportation cost is a fundamental element in the wide price discrep­ ancies that occur between surplus and deficit locations. From the field to the mar­ ket, wheat is transported in bulk and bags. Internal markets are typically served by road and rail, with waterways serving as the primary mode of export. However, highways are also utilized to transport people between adjacent countries that are linked by road. The following factors should be considered while choosing a form of transportation: • • • • •

It will be more economical than the other options. Its purpose is to save wheat from adverse weather. The delivery to the consignee should be made on time. It must be insured. It should be producer-friendly in terms of transportation payment.

3.3.8 Some of the Profitable Flour Mill Business Ideas Wheat germ oil: It is derived from the germ of the wheat kernel, which accounts for only 2–3% of the kernel’s weight. It’s refined vegetable oil with a lot of natural vitamin E, which is a natural antioxidant, as well as a lot of unsaponifiable fraction. Its fatty acid composition has a significant amount of essential fatty acids, which aid in cell renewal. Wheat germ oil contains a high concentration of octacosanol, a long-chain saturated primary alcohol found in a variety of vegetable waxes. Wheat starch and wheat gluten: Starch is a major carbohydrate found in wheat. Gluten, the primary protein in wheat, is used to make wheat gluten. It’s made by scrubbing wheat flour dough with water until all the starch granules are gone, leaving a sticky, insoluble gluten mass that’s baked before being eaten. Atta, maida, suji, and wheat bran: Wheat is ground into a variety of flours, includ­ ing coarse flour, flour, semolina, bran, and wheat germ. It is also utilised in compound feeds, starch synthesis, and as a feedstock in the manufacturing of ethanol. Bakery plant: Bread has become one of the important food items in the modern human diet. It is the most widely consumed wheat-based bakery product, such as breads, biscuits, and other pastries. Bread requires wheat flour, yeast, sugar, salt, water, and a shortening agent as raw components.

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3.3.9 Market Practices and Constraints Marketing channels are a collection of interconnected intermediaries that sell produce from producer to consumers. The following are most prevalent wheat distri­ bution channels: (4)

(i) Private channel: It includes private sector organisations. (ii) Institutional channel: It includes both public and cooperative sector organisations. It is vital to the purchase and distribution of wheat.

3.3.10 Cost and Margin Marketing cost: Marketing expenses are the entire costs incurred during the sale and purchase of the produce until they reach the final consumer. These are some of them: • Handling fees. • Storage and transportation fees. • Handling fees levied by wholesalers and retailers for handling. • Additional costs for supplementary services such as finance, risk, and market information. Marketing margin: The profits of the many market functionaries involved in mar­ keting the product from its initial point of manufacturing until it reaches the final user are referred to as marketing margins. By improving the efficiency of the marketing system, marketing costs can be decreased. Handling large quantities of product at once lowers marketing costs and improves efficiency. Marketing costs are reduced thanks to improved handling, packing, and labour efficiency. Adopting tried-and-true management strategies lowers marketing expenditures. Selling value-added items lowers the marketing expenses. Agricultural commodities have larger marketing margins due to the inherent risk at various phases of the selling process. The following precautions may help to lessen the risk: • Hedging activities, effective market news services, grading, • Increased competitiveness in the selling of farm products are all being implemented. The overall marketing margin’s absolute value fluctuates based on the following factors: Market fee: It is calculated on the basis of the weight of the produce or the value of the product. The buyers are usually the ones who collect it. The market charge varies from one state to the next. Commission: In most cases, commission payments are made in cash. It varies depending on the market. Taxes: Tolls, terminal taxes, sales taxes, octroi, and other taxes are levied in different markets. Typically, the seller is responsible for these taxes.

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Miscellaneous charges: In addition, there are various other fees that must be paid. Handling, weighing, loading, unloading, cleaning, and monetary and in-kind charitable contributions are just a few examples. These fees are paid by either the vendor or the buyer. Farmers use marketing data to plan their production and marketing of their products. It is also vital for market participants to make the best trading selections possible.

3.3.11 Information Technology Applications Information technology has penetrated many aspects of human life and has become an indispensable information tool. To speed agricultural research and development, latest innovation in information technology should be adopted. Selected APMC (Agricultural Produce & Livestock Market Committee) are given computers, peripherals, and soft­ ware in order to broadcast daily market information such as arrivals and prices. In Madhya Pradesh, ITC’s e-chaupals have done commendable work on soy­ bean production and raw material availability for processing. The establishment of “Agriclinic or Agribusiness Centre and Kisan Cell” will allow farmers to get immedi­ ate help with their difficulties over the phone. Kisan call centres are already opera­ tional and offering assistance to struggling farmers. National Agriculture Market (e-NAM) – National Agriculture Market (e-NAM) is expanding to ease farmers. The pan-India trading portal is helping realize the vision of “One Nation, One Market” for agri-produce. National Agriculture Market, or e-NAM, was an innovative agricultural marketing initiative that aimed to improve farmers’ digital access to multiple markets and buyers, as well as bring transparency to trade transactions, with the goal of improving price discovery mechanisms and quality-commensurate price realisation and developing the concept of “One Nation One Market” for agricultural produce. e-NAM improved market linkage by integrat­ ing 1,000 markets across 18 states and three UTs. On the e-NAM platform, more than 1.69 crore farmers and 1.55 lakh traders have registered so far. Farmers are increasingly trading on the e-NAM platform due to the online and transparent bid­ ding procedure. e-NAM is expanding into “Platforms of Platforms” to create a digital ecosystem that uses individual platforms’ expertise across various aspects of the agri­ cultural value chain, such as building and integrating service platforms with e-NaM (QC services, transportation, and delivery). e-NAM is more than a programme – it’s a journey that aspires to assist last-mile farmers and improve the industry. Our farm­ ers will profit greatly from this intervention in terms of increasing their revenue by allowing them to obtain competitive and remunerative pricing in a transparent manner without incurring additional costs (Anonymous, 2021).

3.3.12 Constraints in Wheat Supply Chain There are constraints at various stages of wheat supply chain as described here. • Insufficient storage facilities. • Lack of grading of wheat in the market despite the premium price of graded wheat.

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Wheat Science • Due to high truck transportation costs and a market oversupply, the major­ ity of wheat producers sell their crop at the village level to village traders, itinerant merchants, and other small businesses. Small/marginal farmers are the ones that are most affected by the transportation issue. • The markets are overwhelmed with wheat arrivals during the peak postharvest period, producing a slew of issues such as storage, selling space, and traffic congestion. Distress sales are a typical occurrence as a result of excessive supply and the resulting in surplus wheat in the market. • Farmer financial problems have a crucial part in the adoption of new tech­ nology, resulting in increased losses and deterioration of quality. • Farmers are frequently unaware of market information such as supply, demand, current market pricing, market charges, and so on, which are criti­ cal for making timely decisions.

3.4 Conclusion The rigorous adoption of conventional rice–wheat system in the north western and eastern plain zones instigated detrimental effects on soil quality, nutrient balance, irrigation water budget, crop response, quality, and profitability. The substitution of exhaustive tillage practices with resource-conserving tillage system (zero, strip, and reduced tillage) with or without recycling of crop residue at least in the wheat crop mitigated these issues to some extent. The quality, suitability of wheat for value chain, and profitability can be assured only after the adoption of the latest technologies and proper management of entire wheat chain on every front. The timely and proper man­ agement of sowing/planting, nutrient application, water application, weeds control, disease control, harvesting, and threshing in the recommended way remains pre­ requisite for improving the productivity, resource utilization efficiency, profitability, quality, and suitability of wheat for value addition in addition to reduced losses. The post-harvest management activities take a strategic role in the vertical intensification of harvested wheat grain to wheat-based products for consumers. The selling of valueadded wheat products attracts the attention of consumer and ensures premium market price in contrast to the bulk selling of harvested grains at a local level. However, proper and adequate storage facility remains an essential need to reduce the losses due to grain pests and to have high shelf life of value-added wheat products. The awareness of farmers about various pre-harvest management activities concerning yield, quality and profitability, various parameters and regulations for suppling the raw material in wheat industry, and the importance of value addition for attracting a premium market price would be helpful for wheat supply chain.

REFERENCES Aggarwal, G. C., Sidhu, A. S., Sekhon, N. K., Sandhu, K. S., & Sur, H. S. (1995). Puddling and N management effects on crop response in a rice-wheat cropping system. Soil and Tillage Research, 36(3–4), 129–139. Ahuja, S. S., Rikhi, P., & Dogra, B. (2007). Economics of harvesting and threshing of wheat and paddy in northern India. Journal of Agricultural Engineering, 44(2), 14–19.

Pre- and Post-Harvest Management of Wheat

95

AICRP on STCR [AICRP on Soil Test Crop Response Correlation]. Four decades of STCR research – crop wise recommendations. ICAR-Indian Institute of Soil Science, Bhopal. https://iiss.icar.gov.in/downloads/stcr%20Crop%20wise%20Recommendations.pdf (Accessed 25 April 2023) Alam, A. (2000). Farm mechanization: Rising energy intensity.  The Hindu Survey of Indian Agriculture, pp. 181–191. Alkhafaji, A. J. (2020). Designing and testing of triple combination tillage implement. Plant Archives, 20(1), 2363–2366. Amentae, T. K., Hamo, T. K., Gebresenbet, G., & Ljungberg, D. (2017). Exploring wheat value chain focusing on market performance, post-harvest loss, and supply chain management in Ethiopia: The case of Arsi to Finfinnee market chain.  Journal of Agricultural Science, 9(8), 22. Anonymous (2021). National Agriculture Market (e-NAM) is expanding to ease farmers. Ministry of Agriculture & Farmers Welfare, Government of India. https://pib.gov.in/ PressReleasePage.aspx?PRID=1695193 (Accessed 26 Aug 2022). Anpat, R. M., & Raheman, H. (2017). Investigations on power requirement of active-pas­ sive combination tillage implement. Engineering in Agriculture, Environment and Food, 10(1), 4–13. Aujla, S. S., Sharma, I., Singh, P., Singh, G., Dhaliwal, H. S.,  & Gill, K. S. (1989). Propiconazole-a promising fungicide against Karnal bunt of wheat. Pesticides,  23, 35–38. Ayars, J. E., Phene, C. J., Hutmacher, R. B., Davis, K. R., Schoneman, R. A., Vail, S. S., & Mead, R. M. (1999). Subsurface drip irrigation of row crops: a review of 15 years of research at the Water Management Research Laboratory.  Agricultural Water Management, 42(1), 1–27. Balsari, P., Biglia, A., Comba, L., Sacco, D., Alcatrao, L. E., Varani, M., Mattetti, M., Barge, P., Tortia, C., Manzone, M.,  & Gay, P. (2021). Performance analysis of a tractorpower harrow system under different working conditions. Biosystems Engineering, 202, 28–41. Baoua, I. B., Amadou, L., Bakoye, O., Baributsa, D., & Murdock, L. L. (2016). Triple bag­ ging hermetic technology for post-harvest preservation of paddy rice Oryza sativa L. in the Sahel of West Africa. Journal of Stored Products Research, 68, 73–79. Basavaraja, H., Mahajanashetti, S. B.,  & Udagatti, N. C. (2007). Economic analysis of post-harvest losses in food grains in India: A case study of Karnataka. Agricultural Economics Research Review, 20(1), 117–126. Bashyal, B. M., Rawat, K., Sharma, S., Gogoi, R., & Aggarwal, R. (2020). Major seedborne diseases in important cereals: Symptomatology, aetiology and economic importance. In Seed-Borne Diseases of Agricultural Crops: Detection, Diagnosis & Management (pp. 371–426). Singapore: Springer. Batish, D. R., Kaur, M., Singh, H. P., & Kohli, R. K. (2007). Phytotoxicity of a medicinal plant, Anisomeles indica, against Phalaris minor and its potential use as natural herbicide in wheat fields. Crop Protection, 26(7), 948–952. Belmain, S., & Stevenson, P. (2001). Ethnobotanicals in Ghana: reviving and modernising age-old farmer practice. Pesticide Outlook, 12(6), 233–238. Benaseer, S., Masilamani, P., Albert, V. A., Govindaraj, M., Selvaraju, P., & Bhaskaran, M. (2018). Impact of harvesting and threshing methods on seed quality-A review. Agricultural Reviews, 39(3), 183–192. Bhatt, R., Kukal, S. S., Busari, M. A., Arora, S.,  & Yadav, M. (2016). Sustainability issues on rice–wheat cropping system. International Soil and Water Conservation Research, 4(1), 64–74.

96

Wheat Science

Bijay-Singh, Sharma, R. K., Jat, M. L., Martin, K. L., Chandna, P., Choudhary, O. P., Gupta, R. K., .  .  .  & Gupta, R. (2011). Assessment of the nitrogen management strategy using an optical sensor for irrigated wheat.  Agronomy for Sustainable Development, 31(3), 589–603. Bijay-Singh, Singh, Y., Ladha, J. K., Bronson, K. F., Balasubramanian, V., Singh, J., & Khind, C. S. (2002). Chlorophyll meter–and leaf color chart–based nitrogen manage­ ment for rice and wheat in Northwestern India. Agronomy Journal, 94(4), 821–829. Blackshaw, R. E., Molnar, L. J., & Janzen, H. H. (2004). Nitrogen fertilizer timing and application method affect weed growth and competition with spring wheat. Weed Science, 52(4), 614–622. Blackshaw, R. E., O’Donovan, J. T., Harker, K. N., & Li, X. (2002, September). Beyond herbicides: new approaches to managing weeds. In Proceedings of the International Conference on Environmentally Sustainable Agriculture for Dry Areas (pp. 305– 312), 15–19 September 2002, Shijiazhuang, People’s Republic of China. Bolton, M. D., Kolmer, J. A., & Garvin, D. F. (2008). Wheat leaf rust caused by Puccinia triticina. Molecular plant pathology, 9(5), 563–575. Bovas, J. J. L., Udhayakumar, R., James, P. S., Muthiah, A., Khatawkar, D. S., & James, A. (2022). Combined and multifunctional implements: A promising approach for modern farm mechanization. Biological Forum—An International Journal, 14(1), 1376–1383. Bowman, D., & Hodge, G. (2009). Nanotechnology products in Australia: chemicals, cos­ metics and regulatory character.  In G. Hodge, D. Bowman, & K. Ludlow (Eds.), New Global Frontiers in Regulation: The Age of Nanotechnology. Edward Elgar Publisher, pp. 239–264. Brown, D. W.,  & Proctor, R. H. (2013).  Fusarium: Genomics, Molecular and Cellular Biology. Norfolk: Caister Academic Press. Cao, Q., Miao, Y., Feng, G., Gao, X., Liu, B., Liu, Y., Li, F., Khosla, R., Mulla, D. J., & Zhang, F. (2017). Improving nitrogen use efficiency with minimal environmental risks using an active canopy sensor in a wheat-maize cropping system. Field Crops Research, 214, 365–372. Chaudhary, V. P., & Singh, B. (2002). Effect of zero, strip and conventional till system on performance of wheat. Journal of Agricultural Engineering, 39(2), 27–31. Chauhan, B. S., Mahajan, G., Sardana, V., Timsina, J., & Jat, M. L. (2012). Productivity and sustainability of the rice–wheat cropping system in the Indo-Gangetic Plains of the Indian subcontinent: problems, opportunities, and strategies.  Advances in agronomy, 117, 315–369. Chen, J., Zhao, C., Jones, G., Yang, H., Li, Z., Yang, G., Chen, L., & Wu, Y. (2022). Effect and economic benefit of precision seeding and laser land leveling for winter wheat in the middle of China. Artificial Intelligence in Agriculture, 6, 1–9. Chen, W., Wellings, C., Chen, X., Kang, Z.,  & Liu, T. (2014). Wheat stripe (yellow) rust caused by Puccinia striiformis f. sp. tritici. Molecular Plant Pathology, 15(5), 433–446. Chen, X. M. (2005). Epidemiology and control of stripe rust [Puccinia striiformis f. sp. tritici] on wheat. Canadian Journal of Plant Pathology, 27(3), 314–337. Chen, Y., Liu, T., Tian, X., Wang, X., Li, M., Wang, S., & Wang, Z. (2015). Effects of plas­ tic film combined with straw mulch on grain yield and water use efficiency of winter wheat in Loess Plateau. Field Crops Research, 172, 53–58. Chhokar, R. S., Sharma, R. K., Gill, S. C., Singh, R. K., Joon, V., Kajla, M., & Chaudhary, A. (2018). Suitable wheat cultivars and seeding machines for conservations agri­ culture in rice-wheat and sugarcane-wheat cropping system. Wheat and Barley Research, 10(2), 78–88. Chhokar, R. S., Sharma, R. K.,  & Sharma, I. (2012). Weed management strategies in wheat-A review. Journal of Wheat Research, 4(2), 1–21.

Pre- and Post-Harvest Management of Wheat

97

Choudhary, S., Upadhyay, G., Patel, B., & Jain, M. (2021). Energy requirements and tillage performance under different active tillage treatments in sandy loam soil. Journal of Biosystems Engineering, 46(4), 353–364. Chouhan, S. S., Awasthi, M. K., & Nema, R. K. (2014). Maximizing water productivity and yields of wheat based on drip irrigation systems in clay loam soil. International Journal of Engineering Research & Technology, 3, 533–535. Collavo, A., Panozzo, S., Lucchesi, G., Scarabel, L., & Sattin, M. (2011). Characterisation and management of Phalaris paradoxa resistant to ACCase-inhibitors.  Crop Protection,  30(3), 293–299. Darshan, K., Aggarwal, R., Bashyal, B. M., Singh, J., Shanmugam, V., Gurjar, M. S., & Solanke, A. U. (2020). Transcriptome profiling provides insights into potential antagonistic mechanisms involved in Chaetomium globosum against Bipolaris sorokiniana. Frontiers in Microbiology, 11, 578115. Dayal, G., Sharma, A. K., Mishra, C. N., Kamble, U. R., Kumar, R., & Gaurav, S. S. (2021). Mechanical seed processing improves the seed quality and reduces Karnal Bunt incidence in seed lots of varied wheat cultivars. Journal of Cereal Research, 13(S1), 51–56. De Groote, H., Kimenju, S. C., Likhayo, P., Kanampiu, F., Tefera, T.,  & Hellin, J. (2013). Effectiveness of hermetic systems in controlling maize storage pests in Kenya. Journal of Stored Products Research, 53, 27–36. DES [Directorate of Economics and Statistics] (2022). Fourth advance estimates of pro­ duction of foodgrains for 2021–22. Department of Agriculture and Farmers Welfare, Ministry of Agriculture and Farmers Welfare, Government of India. https://eands. dacnet.nic.in/Advance_Estimate/Time%20Series%204%20AE%202021-22%20 (English).pdf (Accessed 23 Aug 2022). Destain, M. F., & Houmy, K. (1990). Effects of design and kinematic parameters of rotary cultivators on soil structure. Soil and Tillage Research, 17(3–4), 291–301. Dill-Macky, R., & Jones, R. K. (2000). The effect of previous crop residues and tillage on Fusarium head blight of wheat. Plant Disease, 84(1), 71–76. Dineshkumar, S. P., Patil, B. N., Hiremath, S. M., Koti, R. V., Angadi, V. V., & Basavaraj, B. (2013). Nitrogen management through leaf colour chart (LCC) on growth, yield and yield attributes of emmer wheat [Triticum dicoccum (Schrank.) Schulb.] under irrigated condition.  Karnataka Journal of Agricultural Sciences,  26(3), 350–355. Dixit, A., Manes, G. S., Cheetu, G. D., Prakash, A., & Panwar, P. (2014). Adoption status of roto seed drill in Punjab. Agricultural Engineering Today, 38(3), 24–27. Dixit, A. K., Jha, S. N., & Kudos, S. K. A. (2015). Four Decades: R&D of All India Coordinated Research Project on Post-Harvest Engineering and Technology. Ludhiana: ICARCentral Institute of Post-Harvest Engineering and Technology. Figueroa, M., Hammond-Kosack, K. E., & Solomon, P. S. (2018). A review of wheat dis­ eases—a field perspective. Molecular Plant Pathology, 19(6), 1523–1536. Gangwar, K. S., Singh, K. K., Sharma, S. K.,  & Tomar, O. K. (2006). Alternative till­ age and crop residue management in wheat after rice in sandy loam soils of IndoGangetic plains. Soil and Tillage Research, 88(1–2), 242–252. García-Lara, S., García-Jaimes, E., & Ortíz-Islas, S. (2020). Field effectiveness of improved hermetic storage technologies on maize grain quality in Central Mexico. Journal of Stored Products Research, 87, 101585. Gharsan, F. N., Kamel, W. M., Alghamdi, T. S., Alghamdi, A. A., Althagafi, A. O., Aljassim, F. J., & Al-Ghamdi, S. N. (2022). Toxicity of citronella essential oil and its nanoemulsion against the sawtoothed grain beetle Oryzaephilus surinamensis (Coleoptera: Silvanidae). Industrial Crops and Products, 184, 115024.

98

Wheat Science

Ghosh, M., Swain, D. K., Jha, M. K., Tewari, V. K., & Bohra, A. (2020). Optimizing chloro­ phyll meter (SPAD) reading to allow efficient nitrogen use in rice and wheat under ricewheat cropping system in eastern India. Plant Production Science, 23(3), 270–285. Gilbert, J., & Haber, S. (2013). Overview of some recent research developments in Fusarium head blight of wheat. Canadian Journal of Plant Pathology, 35(2), 149–174. Grover, D. K., & Singh, J. M. (2013). Post-harvest losses in wheat crop in Punjab: past and present. Agricultural Economics Research Review, 26(2), 293–297. Gupta, A., Kumar, A., Kumar, R., & Verma, K. (2020). Evaluation of foliar applications at different growth stages and soil amendment for management of Karnal bunt disease in wheat. Seed Research, 48(1), 25–28. Gupta, A.,  & Kumar, R. (2020). Management of seed-borne diseases: an integrated approach. In Seed-Borne Diseases of Agricultural Crops: Detection, Diagnosis & Management (pp. 717–745). Singapore: Springer. Gupta, R. K. (2003). Production constraints of the rice-wheat system In: Addressing Resource Conservation Issues in Rice-Wheat Systems of South Asia: A  Resource Book. Rice Wheat Consortium for Indo-Gangetic Plains – International Maize and Wheat Improvement Centre, New Delhi, India, pp 32–33. Gupta, R. K. (2006). Crop canopy sensors for efficient nitrogen management in the Indo-Gangetic plains (Progress report. USDA funded project). In The Rice-Wheat Consortium, New Delhi International Maize and Wheat Improvement Center (CIMMYT) (p. 28). Mexico: CIMMYT. Gupta, R. K., Guroo, M. A., Gani, M., Bali, K., & Kour, R. (2022). Technological innova­ tions for the management of insect-pests in stored grains. In New Horizons in Wheat and Barley Research (pp. 309–319). Singapore: Springer. Harrison, H. P. (1991). Rotor power and losses of an axial-flow combine. Transactions of the ASAE, 34(1), 60–64. Harrison, H. P. (1992). Grain separation and damage of an axial-flow. Canadian Agricultural Engineering, 34(1), 49. Hassan, M. M., & Gregory, P. J. (1999). Water transmission properties as affected by crop­ ping and tillage systems. Pakistan Journal of Soil Science, 16, 29–38. Hensh, S., Tewari, V. K.,  & Upadhyay, G. (2021). An instrumentation system to mea­ sure the loads acting on the tractor PTO bearing during rotary tillage. Journal of Terramechanics, 96, 1–10. Hossain, M. I., Hossain, I., Mamun, M. A. A., Siddiquie, N. A., Rahman, M. M.,  & Rahman, M. S. (2012). Two-wheel tractor operated strip tillage seeding equipment for dry land farming. International Journal of Energy Machinery, 5(1), 35–41. Huerta-Espino, J., Singh, R. P., German, S., McCallum, B. D., Park, R. F., Chen, W. Q., . . . & Goyeau, H. (2011). Global status of wheat leaf rust caused by Puccinia tri­ ticina. Euphytica, 179(1), 143–160. Hussain, F., Bronson, K. F., Yadvinder, S., Singh, B.,  & Peng, S. (2000). Use of chlo­ rophyll meter sufficiency indices for nitrogen management of irrigated rice in Asia. Agronomy Journal, 92(5), 875–879. IARI. (2012). Crop Residues Management With Conservation Agriculture: Potential, Constraints and Policy Needs. New Delhi: Indian Agriculture Research Institute. ICAR-IIWBR (2021). Wheat crop health newsletter. In: S. Kumar, P. Jasrotia, P. L. Kashyap, R. Kumar and G. P. Singh (Eds.), ICAR-Indian Institute of Wheat and Barley Research (vol. 27, p. 6). Karnal: ICAR. Iqbal, M., Sheikh, G. S., & Sial, J. K. (1980). Harvesting and threshing losses of wheat with mechanical and conventional methods. Agricultural Mechanization in Asia (Japan), 11(3), 66–70.

Pre- and Post-Harvest Management of Wheat

99

Ishaq, M., Ibrahim, M., Hassan, A., Saeed, M.,  & Lal, R. (2001). Subsoil compaction effects on crops in Punjab, Pakistan. Soil and Tillage Research, 60(3–4), 153–161. Islam, M. S., Salokhe, V. M., Gupta, C. P., & Hoki, M. (1994). Effects of PTO-powered disk tilling on some physical properties of Bangkok clay soil. Soil and Tillage Research, 32(2–3), 93–104. Jabran, K., & Farooq, M. (2013). Implications of potential allelopathic crops in agricul­ tural systems. In Allelopathy (pp. 349–385). Berlin and Heidelberg: Springer. Jabran, K., Farooq, M., Hussain, M.,  & Ali, M. (2010). Wild oat (Avena fatua L.) and canary grass (Phalaris minor Ritz.) management through allelopathy.  Journal of Plant Protection Research, 50(1), 41–44. Jasrotia, P., Nagpal, M., Mishra, C. N., Sharma, A. K., Kumar, S., Kamble, U., Bhardwaj, A. K., Kshyap, P. L., Kumar, S., & Singh, G. P. (2022). Nanomaterials for posthar­ vest management of insect pests: current state and future perspectives. Frontiers in Nanotechnology, 3, 811056. Jat, H. S., Kumar, P., Sutaliya, J. M., Kumar, S., Choudhary, M., Singh, Y., & Jat, M. L. (2019). Conservation agriculture based sustainable intensification of basmati ricewheat system in North-West India. Archives of Agronomy and Soil Science, 65(10), 1370–1386. Jat, M. L., Chandna, P., Gupta, R., Sharma, S. K.,  & Gill, M. A. (2006). Laser Land Leveling: A  Precursor Technology for Resource Conservation. Rice-Wheat Consortium Technical Bulletin Series 7, p. 48. New Delhi: Rice-Wheat Consortium for the Indo-Gangetic Plains. Kailappan, R., Manian, R., Amuthan, G. N., Vijayaraghavan, C., Duraisamy, G. (2001). Combination tillage tool I (design and development of combination tillage tool). Agricultural Mechanization in Asia, Africa and Latin America, 32(3), 19–22. Kalsa, K. K., Subramanyam, B., Demissie, G., Worku, A. F., & Habtu, N. G. (2019). Major insect pests and their associated losses in quantity and quality of farm-stored wheat seed. Ethiopian Journal of Agricultural Sciences, 29(2), 71–82. Kankal, U. S., Karale, D. S., Thakare, S. H., & Khamballkar, V. P. (2016). Performance evaluation of tractor operated rotavator in dry land and wet land field condition. International Journal of Agricultural Science and Research, 6(1), 137–146. Kashyap, P. L., Jasrotia, P., Kumar, S., Singh, D. P., Singh, G. P. (2018). Identification guide for major diseases and insect-pests of wheat. Technical Bulletin no. 18, p. 38. Kaur, B., Singh, S., Garg, B. R., Singh, J. M., & Singh, J. (2012). Enhancing water pro­ ductivity through on-farm resource conservation technology in Punjab agriculture. Agricultural Economics Research Review, 25(347–2016–16901), 79–85. Kavita, P. S. K., Pande, K. S. K.,  & Yadav, J. K. (2017). In vitro evaluation of fungi­ cides against Bipolaris sorokiniana causing spot blotch of barley (Hordeum vul­ gare L.).  International Journal of Current Microbiology and Applied Sciences, 6, 4734–4739. Kerstin, H., & Charity, M. (2011). Aflatoxin control and prevention strategies in key crops of Sub-Saharan Africa. African Journal of Microbiology Research, 5(5), 459–466. Khan, A. U. (1990). Dual-mode all-crop thresher for Egyptian conditions. Agricultural Mechanization in Asia, Africa and Latin America, 21(4), 11–14. Khan, M. A., & Khan, S. L. (2010). Trade Development Authority of Pakistan Report on Post Harvest Losses of Rice. Karachi: Trade Development Authority of Pakistan. Kharrou, M. H., Er-Raki, S., Chehbouni, A., Duchemin, B., Simonneaux, V., Le Page, M., . . . & Jarlan, L. (2011). Water use efficiency and yield of winter wheat under differ­ ent irrigation regimes in a semi-arid region. Agricultural Sciences in China, 2(3), 273–282.

100

Wheat Science

Khurana, H. S., Phillips, S. B., Alley, M. M., Dobermann, A., Sidhu, A. S.,  & Peng, S. (2008). Agronomic and economic evaluation of site-specific nutrient management for irrigated wheat in northwest India. Nutrient Cycling in Agroecosystems, 82(1), 15–31. Kukal, S. S., & Aggarwal, G. C. (2003). Puddling depth and intensity effects in rice–wheat system on a sandy loam soil: I. Development of subsurface compaction.  Soil and Tillage Research, 72(1), 1–8. Kumar, A., Gupta, A., Atwal, S. S., Maheshwari, V. K., & Singh, C. B. (2015). Post har­ vest management of Karnal Bunt, a quarantine disease in wheat. Plant Pathology Journal (Faisalabad), 14(1), 23–30. Kumar, A., Kumar, A., Khan, K.,  & Kumar, D. (2017). Performance evaluation of har­ vesting and threshing methods for wheat crop. International Journal of Pure and Applied Bioscience, 5(2), 604–611. Kumar, A., Kumar, A., Kumar, S., & Chandra, S. (2019). Performance evaluation and eco­ nomics of the reaper-cum-binder machine for the mechanized harvesting of wheat crop at Madhubani district of Bihar. Journal of Pharmacognosy and Phytochemistry, 8(4), 63–68. Kumar, D., & Kalita, P. (2017). Reducing postharvest losses during storage of grain crops to strengthen food security in developing countries. Foods, 6(1), 8. Kumar, N., Chaudhary, A., Ahlawat, O. P., Naorem, A., Upadhyay, G., Chhokar, R. S., Gill, S. C., Khippal, A., Tripathi, S. C., & Singh, G. P. (2023). Crop residue management challenges, opportunities and way forward for sustainable food-energy security in India: A review. Soil and Tillage Research, 228, 105641. Kumar, N., Chhokar, R. S., Meena, R. P., Kharub, A. S., Gill, S. C., Tripathi, S. C., . . . & Singh, G. P. (2022). Challenges and opportunities in productivity and sustainability of rice cultivation system: a critical review in Indian perspective. Cereal Research Communications, 50, 573–601. Kumar, N., Chhokar, R. S., Tripathi, S. C., Sharma, R. K., Gill, S. C., & Kumar, M. (2020). Role of conservation agriculture in sustainable food production and challenges. Findings in Agricultural Research and Management (FARM) Journal, 4(2), 5–11. Kumar, R. (2009). Irrigate Wheat in a Proper Way. Agropedia, India. http://agropedia.iitk. ac.in/content/irrigate-wheat-proper-way (Accessed 25 April 2023) Kumar, R. (2017).  Insect Pests of Stored Grain: Biology, Behavior, and Management Strategies (1st ed.). New York: Apple Academic Press. Kumar, R.,  & Gupta, A. (Eds.). (2020).  Seed-Borne Diseases of Agricultural Crops: Detection, Diagnosis & Management (pp. 1–871). Singapore: Springer. Ladha, J. K., Pathak, H., & Gupta, R. K. (2007). Sustainability of the rice-wheat cropping system: issues, constraints, and remedial options. Journal of Crop Improvement, 19(1–2), 125–136. Lashgari, M., Mobli, H., Omid, M., Alimardani, R., & Mohtasebi, S. S. (2008). Qualitative analysis of wheat grain damage during harvesting with John Deere combine har­ vester. International Journal of Agriculture and Biology, 10(2), 201–204. Li, F., Miao, Y., Zhang, F., Cui, Z., Li, R., Chen, X., Xhang, H., Schroder, J., Raun, W. R., & Jia, L. (2009). In-season optical sensing improves nitrogen-use efficiency for winter wheat. Soil Science Society of America Journal, 73(5), 1566–1574. Likhayo, P., Bruce, A. Y., Mutambuki, K., Tefera, T., & Mueke, J. (2016). On-farm evalu­ ation of hermetic technology against maize storage pests in Kenya.  Journal of Economic Entomology, 109(4), 1943–1950. Liu, H. J., Kang, Y., Yao, S. M., Sun, Z. Q., Liu, S. P., & Wang, Q. G. (2013). Field evalu­ ation on water productivity of winter wheat under sprinkler or surface irrigation in the North China plain. Irrigation and Drainage, 62(1), 37–49.

Pre- and Post-Harvest Management of Wheat

101

Lohan, S. K., Jat, H. S., Yadav, A. K., Sidhu, H. S., Jat, M. L., Choudhary, M., Peter, J. K., & Sharma, P. C. (2018). Burning issues of paddy residue management in north­ west states of India. Renewable and Sustainable Energy Reviews, 81, 693–706. Magar, P. B., Baidya, S., Koju, R., & Adhikary, S. (2020). In-vitro evaluation of botanicals and fungicides against Bipolaris sorokiniana, causing spot blotch of wheat. Journal of Agriculture and Natural Resources, 3(2), 296–305. Malik, R. K., & Singh, S. (1993). Evolving strategies for herbicide use in wheat: resistance and integrated weed management. In Proceedings of an Indian Society of Weed Science: International Symposium (pp. 225–238), 18–20 November 1993, Hisar, India. Malik, R. K.,  & Singh, S. (1995). Littleseed canarygrass (Phalaris minor) resistance to isoproturon in India. Weed Technology, 9(3), 419–425. Marenya, M. O., & du Plessis, H. M. (2006). Torque requirements and forces generated by a deep tilling down-cut rotary tiller. In 2006 ASAE Annual Meeting (p. 1). New York: American Society of Agricultural and Biological Engineers. McMullen, M., Bergstrom, G., De Wolf, E., Dill-Macky, R., Hershman, D., Shaner, G., & Van Sanford, D. (2012). A  unified effort to fight an enemy of wheat and barley: Fusarium head blight. Plant Disease, 96(12), 1712–1728. Meena, R. P., Karnam, V., Tripathi, S. C., Jha, A., Sharma, R. K., & Singh, G. P. (2019). Irrigation management strategies in wheat for efficient water use in the regions of depleting water resources. Agricultural Water Management, 214, 38–46. Mehta, C. R., Singh, K., & Selvan, M. M. (2011). A decision support system for selection of tractor–implement system used on Indian farms. Journal of Terramechanics, 48(1), 65–73. Mehta, Y. R. (1993). Spot blotch. In Seedborne Diseases and Seed Health Testing of Wheat (pp 105–112). Copenhagen: Jordburgsforlaget. Mitra, M. (1931). A new bunt on wheat in India. Annals of Applied Biology, 18, 178–179. Mobolade, A. J., Bunindro, N., Sahoo, D., & Rajashekar, Y. (2019). Traditional methods of food grains preservation and storage in Nigeria and India. Annals of Agricultural Sciences, 64(2), 196–205. Mohapatra, D., Kar, A., & Giri, S. K. (2015). Insect pest management in stored pulses: An overview. Food and Bioprocess Technology, 8(2), 239–265. Mojid, M. A., & Hossain, A. Z. (2013). Conjunctive use of saline and fresh water for irrigat­ ing Wheat (Triticum aestivum L.) at different growth stages. The Agriculturists, 11(1), 15–23. Mondal, S., Chakraborty, D., Das, T. K., Shrivastava, M., Mishra, A. K., Bandyopadhyay, K. K., Aggarwal, P.,  & Chaudhari, S. K. (2019). Conservation agriculture had a strong impact on the sub-surface soil strength and root growth in wheat after a 7-year transition period. Soil and Tillage Research, 195, 104385. Morrison III, W. R., Bruce, A., Wilkins, R. V., Albin, C. E.,  & Arthur, F. H. (2019). Sanitation improves stored product insect pest management. Insects, 10(3), 77. Moumouni, D. A., Doumma, A., & Seyni, I. S. (2014). Effect of solar drying on the biolog­ ical parameters of the cowpea weevil, Callosobruchus maculatus Fab. (ColeopteraBruchinae), in Sahelian area. Journal of Applied Biosciences, 84, 7723–7729. Mrema, G., Soni, P., & Rolle, R. S. (2014). A regional strategy for sustainable agricultural mechanization: sustainable mechanization across agri-food chains in Asia and the Pacific region. Food and Agriculture Organization of the United Nations Regional Office for Asia and the Pacific [RAP Publication (2014/24)]. Murumkar, R. P., Dongarwar, U. R., Borkar, P. A., Pisalkar, P. S., & Phad, D. S. (2014). Performance evaluation of self-propelled vertical conveyor reaper. International Journal of Science, Environment and Technology, 3(1), 1701–1705.

102

Wheat Science

Nadeem, M., Iqbal, M., Farooque, A., Munir, A., Ahmad, M., & Zaman, Q. (2015). Design and evaluation of self propelled reaper for harvesting multi crops. In 2015 ASABE Annual International Meeting (p. 1). New York: American Society of Agricultural and Biological Engineers. Nalavade, P. P., Salokhe, V. M., Niyamapa, T., & Soni, P. (2010). Performance of free roll­ ing and powered tillage discs. Soil and Tillage Research, 109(2), 87–93. Nataraj, E., Sarkar, P., Raheman, H., & Upadhyay, G. (2021). Embedded digital display and warning system of velocity ratio and wheel slip for tractor operated active tillage implements. Journal of Terramechanics, 97, 35–43. Oerke, E. C. (2006). Crop losses to pests.  The Journal of Agricultural Science,  144(1), 31–43. Ogendo, J. O., Deng, A. L., Belmain, S. R., Walker, D. J., & Musandu, A. A. O. (2004). Effect of insecticidal plant materials, Lantana camara L. and Tephrosia vogelii Hook, on the quality parameters of stored maize grains. Journal of Food Technology in Africa, 9(1), 29–35. Pampolino, M., Majumdar, K., Jat, M. L., Satyanarayana, T., Kumar, A., Shahi, V. B., Gupta, N., & Singh, V. (2012). Development and evaluation of nutrient expert for wheat in South Asia. Better Crops, 96(3), 29–31. Pandey, M. M., Majumdar, K. L., Singh, G., & Singh, G. (1997). Farm Machinery Research Digest. Agriculture (Technical Bulletin No: CIAE/FIM/1997/69, p.  318). Bhopal: Central Institute of Agricultural Engineering. Parida, B. C. (2008). Evaluation, constraints and acceptability of different types of ver­ tical conveyer reaper for harvesting rice in coastal Orissa, India. Agricultural Mechanization in Asia, Africa & Latin America, 39(1), 29. Parihar, R. K., Devedee, A. K., & Verma, S. (2018). Leaf colour chart: a resource conser­ vation technology. Agrobios Newsletter, XVII(1), 28. Patel, S. K.,  & Varshney, B. P. (2014). Modeling of wheat crop harvesting losses. Agricultural Engineering International: CIGR Journal, 16(2), 97–102. Pawar, C. S., Shirsat, N. A., & Pathak, S. V. (2008). Performance evaluation of combine harvester and combination of self-propelled vertical conveyor reaper with thresher for wheat harvesting. Agriculture Update, 3(1–2), 123–126. Petrov, A., Saveliev, Y., Ishkin, P.,  & Petrov, M. (2020). Soil tillage energy efficiency increase. BIO Web Conferences, 17, 1–4. Prasad, J. (1996). A comparison between a rotavator and conventional tillage equipment for wheat-soybean rotations on a vertisol in Central India. Soil and Tillage Research, 37(2–3), 191–199. Prescott, J. M., Burnett, P. A., Saari, E. E., Ransom, J. K., Bowman, J. D., De Milliano, W., .  .  .  & Geleta, A. B. (1986). Wheat Diseases and Pests: A  Guide for Field Identification (p. 135). Mexico: CIMMYT. Qiu, G. Y., Wang, L., He, X., Zhang, X., Chen, S., Chen, J.,  & Yang, Y. (2008). Water use efficiency and evapotranspiration of winter wheat and its response to irriga­ tion regime in the north China plain. Agricultural and Forest Meteorology, 148(11), 1848–1859. Raheman, H., & Roul, A. K. (2013). Combination tillage implement for high horse power 2WD tractors. Agricultural Mechanization in Asia, Africa and Latin America, 44(3), 75–79. Rahman, M. M., Islam, W., & Ahmed, K. N. (2009). Functional response of the preda­ tor Xylocoris flavipes to three stored product insect pests. International Journal of Agriculture and Biology, 11(3), 316–320.

Pre- and Post-Harvest Management of Wheat

103

Raj, S. (2021). Studies on Bipolaris sorokiniana, the fungal incitant of spot blotch of wheat (Triticum aestivum L.). M.Sc. Thesis, CCS University, Meerut, p. 50. Rajendran, S.,  & Sriranjini, V. (2008). Plant products as fumigants for stored-product insect control. Journal of Stored Products Research, 44(2), 126–135. Reena, V. C., Dhyani, S. C., Chaturvedi, S., & Gouda, H. S. (2017). Growth, yield and nitrogen use efficiency in wheat as influenced by leaf colour chart and chlorophyll meter based nitrogen management. International Journal of Current Microbiology and Applied Sciences, 6(12), 1696–1704. Safdar, M. E., Asif, M., Ali, A., Aziz, A., Yasin, M., Aziz, M., Afzal, M., & Ali, A. (2011). Comparative efficacy of different weed management strategies in wheat.  Chilean Journal of Agricultural Research, 71(2), 195. Saharan, M. S., Kumar, J., Sharma, A. K., & Nagarajan, S. (2004). Fusarium head blight (FHB) or head scab of wheat-A review.  Proceedings of the National Academy of Sciences, India Section B, 3, 255–268. Sahoo, R. K. (2005). Development and performance evaluation of combination tillage implements for 2wd tractors. Doctoral dissertation, IIT, Kharagpur. Sankar, M. V.,  & Abideen, S. (2015). Pesticidal effect of green synthesized silver and lead nanoparticles using Avicennia marina against grain storage pest Sitophilus ory­ zae. International Journal of Nanomaterials and Biostructures, 5(3), 32–39. Sarkar, D., Datta, V., & Chattopadhyay, K. S. (2013). Assessment of pre and post harvest losses in rice and wheat in West Bengal. Agro-Economic Research Centre, VisvaBharati, Santiniketan, Study No. 172. https://www.visvabharati.ac.in/file/Final­ Report-172.pdf (Accessed 25 April 2023) Sarkar, P., Upadhyay, G., & Raheman, H. (2021). Active-passive and passive-passive con­ figurations of combined tillage implements for improved tillage and tractive perfor­ mance: A review. Spanish Journal of Agricultural Research, 19(4), e02R01. Sattar, M., U-Din, M., Ali, M., Ali, L., Waqar, M. Q., Ali, M. A., & Khalid, L. (2015). Grain losses of wheat as affected by different harvesting and threshing techniques. International Journal of Research in Agriculture and Forestry, 2(6), 20–26. Saurabh, K., Rao, K. K., Mishra, J. S., Kumar, R., Poonia, S. P., Samal, S. K., . . . & Malik, R. K. (2021). Influence of tillage based crop establishment and residue management practices on soil quality indices and yield sustainability in rice-wheat cropping sys­ tem of eastern Indo-Gangetic Plains. Soil and Tillage Research, 206, 104841. Sessiz, A., & Ülger, P. (2003). Determination of threshing losses with a raspbar type axial flow threshing unit. Journal of Agricultural Engineering, 40(4), 1–8. Shahani, W. A., Kaiwen, F., & Memon, A. (2016). Impact of laser leveling technology on water use efficiency and crop productivity in the cotton-wheat cropping system in Sindh. International Journal of Research Granthaalayah, 4(2), 220–231. Shankar, M. S., Ramanjaneyulu, A., Neelima, T., & Das, A. (2015). Sprinkler irrigation– an asset in water scarce and undulating areas. In Integrated Soil and Water Resource Management for Livelihood and Environmental Security (pp.  259–283). Umiam: ICAR Research Complex for NEH Region. Sharma, R. K., Chhokar, R. S., Jat, M. L., Singh, S., Mishra, B., & Gupta, R. K. (2008). Direct drilling of wheat into rice residues: experiences in Haryana and western Uttar Pradesh. Permanent Beds and Rice-Residue Management for Rice-Wheat System of the Indo-Gangetic Plain, pp. 147–158. Shelar, V. R. (2008). Role of mechanical damage in deterioration of soybean seed quality during storage-a review. Agricultural Research, 29(3), 177–184. Shinners, K. J., Alcock, R., & Wilkes, J. M. (1990). Combining active and passive tillage elements to reduce draft requirements. Transactions of the ASAE, 33(2), 400–0404.

104

Wheat Science

Shukla, L. N., Dhaliwal, I. S., Verma, S. R., Tandon, S. K.,  & Chauhan, A. M. (2008) Tractor operated strip-till drill. In Success Stories, AICRP on Farm Implements and Machinery. Bhopal: Central Institute of Agricultural Engineering. Sidhu, H. S., Jat, M. L., Singh, Y., Sidhu, R. K., Gupta, N., Singh, P., Singh, P., Jat, H. S., & Gerard, B. (2019). Sub-surface drip fertigation with conservation agriculture in a rice-wheat system: A breakthrough for addressing water and nitrogen use effi­ ciency. Agricultural Water Management, 216, 273–283. Sidhu, H. S., Singh, M., Singh, Y., Blackwell, J., Lohan, S. K., Humphreys, E., Jat, M. L., Singh, V., & Singh, S. (2015). Development and evaluation of the turbo happy seeder for sowing wheat into heavy rice residues in NW India. Field Crops Research, 184, 201–212. Singano, C. D., Mvumi, B. M., & Stathers, T. E. (2019). Effectiveness of grain storage facil­ ities and protectants in controlling stored-maize insect pests in a climate-risk prone area of Shire Valley, Southern Malawi. Journal of Stored Products Research, 83, 130–147. Singh, B., Humphreys, E., Gaydon, D. S.,  & Eberbach, P. L. (2016). Evaluation of the effects of mulch on optimum sowing date and irrigation management of zero till wheat in central Punjab, India using APSIM. Field Crops Research, 197, 83–96. Singh, D. P., Sharma, A. K., Pankaj, K., Chowdhury, A. K., Singh, K. P., Mann, S. K., . . . & Tewari, A. N. (2008). Management of leaf blight complex of wheat (Triticum aestivum) caused by Bipolaris sorokiniana and Alternaria triticina in different agroclimatic zones using an integrated approach.  Indian Journal of Agricultural Sciences, 78(6), 513–517. Singh, D. V., Agarwal, R., Shrestha, J. K., Thapa, B. R., & Dubin, H. J. (1989). First report of Tilletia indica on wheat in Nepal. Plant Disease, 73(3), 273. Singh, D. V., Pande, S. K., Kavita, Y. J., & Kumar, S. (2018). Bioefficacy of Trichoderma spp. against Bipolaris sorokiniana causing spot blotch disease of wheat and bar­ ley.  International Journal of Current Microbiology and Applied Sciences,  7(3), 2322–2327. Singh, R., & Singh, B. (2004). Effect of irrigation time and weed management practices on weeds and wheat yield. Indian Journal of Weed Science, 36(1–2), 25–27. Singh, R., Singh, A., Kumar, S., Sheoran, P., Rai, A. K., Rani, S., & Yadav, R. K. (2021). Mini-sprinkler irrigation influences water and nitrogen use efficiency and wheat yield in western indo-gangetic plains of India. Journal of Soil Salinity and Water Quality, 13(2), 191–197. Singh, R. V., Singh, A. K., Ahmad, R., & Singh, S. P. (1998). Influence of agronomic prac­ tices on foliar blight, and identification of alternate hosts in rice-wheat cropping sys­ tem. Helminthosporium Blights of Wheat: Spot Blotch and Tan Spot, pp. 346–348. Singh, S., Kirkwood, R. C., & Marshall, G. (1999). Biology and control of Phalaris minor Retz.(littleseed canarygrass) in wheat. Crop Protection, 18(1), 1–16. Singh, S., Malik, R. K., Panwar, R. S., & Balyan, R. S. (1995). Influence of sowing time on winter wild oat (Avena ludoviciana) control in wheat (Triticum aestivum) with isoproturon. Weed Science, 43(3), 370–374. Singh, T. P. (2016). Farm Machinery. New Delhi: PHI Learning Pvt. Ltd. Singh, V., Singh, B., Thind, H. S., Singh, Y., Gupta, R. K., Singh, S., & Balasubramanian, V. (2014). Evaluation of leaf colour chart for need-based nitrogen management in rice, maize and wheat in north-western India. Indian Journal of Research, 51(3), 4. Srivastava, A. K., Mahoney, W. T., & West, N. L. (1990). The effect of crop properties on combine performance. Transactions of the ASAE, 33(1), 63–72.

Pre- and Post-Harvest Management of Wheat

105

Stack, R. W., & McMullen, M. (1988). Root and Crown Rots of Small Grains (p. 8). Fargo: NDSU Extension Service. Sur, H. S., Prihar, S. S.,  & Jalota, S. K. (1980). Effect of rice-wheat and maize-wheat rotations on water transmission and wheat root development in a sandy loam of the Punjab, India. Soil and Tillage Research, 1, 361–371. Teli, B., Chattopadhyay, A., Meena, S. C., Gangwar, G. P., & Pandey, S. K. (2016). Present status of Fusarium head blight of wheat and barley in India. Diseases of Wheat and Their Management, 79–92. Teli, B., Purohit, J., Rashid, M. M., Jailani, A. A. K.,  & Chattopadhyay, A. (2020). Omics insight on fusarium head blight of wheat for translational research perspec­ tive. Current Genomics, 21(6), 411–428. Tfwala, C. M., Mengistu, A. G., Haka, I. B. U., van Rensburg, L. D.,  & Du Preez, C. C. (2021). Seasonal variations of transpiration efficiency coefficient of irrigated wheat. Heliyon, 7(2), e06233. Timsina, J., & Connor, D. J. (2001). Productivity and management of rice–wheat cropping systems: issues and challenges. Field Crops Research, 69(2), 93–132. Timsina, J., Godwin, D., Humphreys, E., Kukal, S. S., & Smith, D. (2008). Evaluation of options for increasing yield and water productivity of wheat in Punjab, India using the DSSAT-CSM-CERES-wheat model. Agricultural Water Management, 95(9), 1099–1110. Tiwari, R. K., & Chauhan, S. K. (2018). Effect of round spiked threshing cylinder geom­ etry on the threshing performance of wheat crop. Indian Journal of Hill Farming, 31(1), 61–67. Tiwari, R. K., Din, M., & Kumar, M. (2018). Power threshers for effective threshing of crops since green revolution-a review. International Journal of Agriculture Sciences, 10(15), 6793–6795. Tiwari, R. K., Singh, Y., Din, M., Chauhan, S. K., & Namdev, A. (2019). Effect of threshing cylinder configuration on wheat straw quality in Indo-Gangetic plains. International Journal of Agriculture Sciences, 11(3), 7813–7817. Tripathi, S. C., Mongia, A. D., Sharma, R. K., Kharub, A. S., & Chhokar, R. S. (2005). Wheat productivity at different sowing dates in various agroclimatic zones of India. SAARC Journal of Agriculture, 3, 191–201. Umair, M., Hussain, T., Jiang, H., Ahmad, A., Yao, J., Qi, Y., Zhang, Y., Min, L.,  & Shen, Y. (2019). Water-saving potential of subsurface drip irrigation for winter wheat. Sustainability, 11(10), 2978. Upadhyay, G., & Raheman, H. (2018). Performance of combined offset disc harrow (front active and rear passive set configuration) in soil bin. Journal of Terramechanics, 78, 27–37. Upadhyay, G.,  & Raheman, H. (2019). Comparative analysis of tillage in sandy clay loam soil by free rolling and powered disc harrow. Engineering in Agriculture, Environment and Food, 12(1), 118–125. Upadhyay, G., & Raheman, H. (2020a). Comparative assessment of energy requirement and tillage effectiveness of combined (active-passive) and conventional offset disc harrows. Biosystems Engineering, 198, 266–279. Usaborisut, P., & Prasertkan, K. (2019). Specific energy requirements and soil pulveriza­ tion of a combined tillage implement. Heliyon, 5(11), e02757. Walker, G. W., Kookana, R. S., Smith, N. E., Kah, M., Doolette, C. L., Reeves, P. T., Lovell, W., Andersen, D. J., Turney, T. W., & Navarro, D. A. (2017). Ecological risk assess­ ment of nano-enabled pesticides: A perspective on problem formulation. Journal of Agricultural and Food Chemistry, 66(26), 6480–6486.

106

Wheat Science

Walter, G. H., Chandrasekaran, S., Collins, P. J., Jagadeesan, R., Mohankumar, S., Alagusundaram, K., Ebert, P. R., Daglish, G. J., Nayak, M. K., Mohan, S., Srivastava, Chitra, Chadda, I. C., Rajagopal, A., Reid, R., & Subramanian, S. (2016). The grand challenge of food security: general lessons from a comprehensive approach to pro­ tecting stored grain from insect pests in Australia and India.  Indian Journal of Entomology, 78(special), 7–16. Watts, C. W.,  & Patterson, D. E. (1984). The development and assessment of high speed shallow cultivation equipment for autumn cereals. Journal of Agricultural Engineering Research, 29(2), 115–122. Wegulo, S. N., Baenziger, P. S., Nopsa, J. H., Bockus, W. W., & Hallen-Adams, H. (2015). Management of Fusarium head blight of wheat and barley.  Crop Protection,  73, 100–107. World Bank Report, (1999) Post-harvest management – fights hunger with FAO. India Grains, 4(3), 20–22. Zahir, A. A., Bagavan, A., Kamaraj, C., Elango, G., & Rahuman, A. A. (2012). Efficacy of plant-mediated synthesized silver nanoparticles against Sitophilus oryzae. Journal of Biopesticides, 5, 95–102.

4 Contribution of Wheat in Global Food Security in Changing Climatic Conditions Challenges Ahead and Coping Strategies Anil Kumar Dixit, Biswajit Sen, Shweta Bijla, Sanjit Maiti, and Babita Kathayat CONTENTS 4.1

Introduction.................................................................................................... 107

4.1.1 Dimensions of Food Security ............................................................ 107

4.1.2 The Bi-Modal Problem of Hunger and Food Security...................... 108

4.2 Materials and Methods................................................................................... 109

4.2.1 Data.................................................................................................... 109

4.2.2 Methodological Design...................................................................... 109

4.3 Results and Discussion................................................................................... 111

4.3.1 Situation Assessment of Food and Nutritional Security:

Worldwide Perspective ...................................................................... 111

4.3.2 Association Between Different Parameters of Food Security .......... 112

4.3.3 Role of Wheat in Food Security........................................................ 113

4.3.4 Wheat Yield and Yield Gap............................................................... 115

4.4 Measures to Maintain and Enhance Wheat Yield ......................................... 116

4.4.1 Varietal Improvement and Training – Institutional Support............. 116

4.4.2 Adoption and Impact of Improved Technologies (Including

Biofortified Varieties) and Natural Resource Practices .................... 117

4.4.2.1 Natural Resource Practices and Zero Tillage.................... 117

4.4.2.2 Biofortification ................................................................... 118

4.5 Conclusions and Policy Implications ............................................................. 119

References................................................................................................................ 120

4.1 Introduction 4.1.1 Dimensions of Food Security Food security is a dynamic concept, and its definition has evolved over time depend­ ing upon the various facets of socio-political development shaped by human values. The term “food security” stemmed out first time in World Food Conference in mid­ 1970s and connoted only the availability dimension. Food security initially meant DOI: 10.1201/9781003307938-4

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‘availability at all times of adequate world food supplies of basic foodstuffs to sustain a steady expansion of food consumption and to offset fluctuations in production and prices’ (United Nations, 1975). The definition was constrained by the availability of food supplies in a macro perspective of food security. So, food security was viewed from the ‘production led’ phenomena. Subsequently, the micro approach of food secu­ rity – ‘ensuring that all people at all times have both physical and economic access to the basic food that they need’ – initiated a ‘production-distribution led’ dimension and included the concepts of accessibility and availability (FAO, 1983). Later, the World Bank’s Poverty and Hunger Report included a ‘temporal effect’ dimension to food security, distinguishing it as chronic food insecurity (long-term) and transitory food insecurity (short-term) (World Bank, 1986).

4.1.2 The Bi-Modal Problem of Hunger and Food Security Maslow’s Need Triangle Theory considered food as basic necessity of life (Maslow and Lewis, 1987). According to studies, between 2014 and 2016, over 11% of the world population’s daily dietary requirements were severely inadequate (FAO, 2018). This problem could get worse by trapping more people in the cycle of food insecu­ rity due to rising population and stagnant food production. By 2050, it is anticipated that there will be more than ten billion people on the planet. Such a population growth scenario may knock the tipping point of food insecurity earlier contrasting the projection of several literatures (von Braun and Birner, 2017; Dillard, 2019). Climate shocks have a significant impact on global food production system in terms of growing variability in production pattern (Ziervogel et al., 2006; Wossen et al., 2018). The current global food production system is majorly affected by climatic shocks in terms of increasing variability in production pattern (Ziervogel et al., 2006; Wossen et al., 2018). These climatic shocks lead to increased production risk, besides, depleting soil health and water quality create detrimental environmental effect (Dillard, 2019). Further, genetic improvement programmes that aim to increase production have also

FIGURE 4.1 Threats to food security.

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created genetic erosion and a reduction in the genetic diversity of the crop species. This led to an increase in susceptibility and less tolerance to various environmental shocks (Esquinas-Alcázar, 2005; Brussaard et al., 2010). These factors jointly create the ‘pull factors’ that pose challenges to food security. In addition to these pull variables, several directly human-led factors (also known as push factors), such as population expansion and post-harvest loss, also pose a threat to food security (Figure 4.1).

4.2 Materials and Methods 4.2.1 Data The present study used different parameters of food and nutritional security across for major 204 countries (Appendix 4.1) for the reference year 2018–2019 (www.fao. org.in). To estimate the role of wheat crop in determining food security of a country, time series of latest 21-year data for wheat yield (reference year: 2000 to 2020) was collected and correlated with food insecurity parameters.

4.2.2 Methodological Design The study assumed food insecurity in any particular region as a multifaceted problem; hence, it cannot be identified separately. To establish the assumption, Zellner and Theil’s (1992) Three Stage Least Square (3SLS) technique was adopted in the study to identify the factors that influence the prevalence of severe food insecurity, share of dietary energy supply derived through cereals and cereal import dependency ratio. 3SLS technique uses full information characteristic so that the estimation of coef­ ficient gains efficiency even though the structural disturbances form non-diagonal moment matrix (Greene, 2018). The system of equation framed is represented here. Prevalence of serve food insecurityi = a 0i + a1i ( ADE)i + a 2i (Y _ wheat))i + a 3i (incm)i + a 4i (rtl _ loss)i + a 5i (cpi )i + ε1i

(4.1)

Share of dietary energy supply derived through cerealsi = b 0i + b1i ( AD DE )i + b 2i (import )i + b 3i ( pol)i + ε 2i

(4.2)

Cereal import dependency ratioi = q 0i + q1i (cpi )i + q 2i (Y _ wheat)i + q3i (Share of dietary energy supply

derived through cereals)i + q 4i ( inncm )i + ε3i

(4.3)

The system of Equations (4.1–4.3) can be framed as

(4.4)

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where y elements describe endogenous left hand side dependent variable list, and Z elements represent both endogenous and exogenous variable list on right hand side. The total number of structured equations (M) are 3. The variables included in the model (Equations (4.1–4.4)) are described below in Table 4.1. The endogenous and exogenous variables included in the empirical econometric model are given as: Endogenous variables: Prevalence of severe food insecurity in total popula­ tion, Share of dietary energy supply derived through cereals, Cereal import dependency ratio Exogenous variables: Average dietary energy supply adequacy, Wheat yield, Per capita income, Incidence of caloric losses at retail, Consumer price index value, Political stability and absence of violence TABLE 4.1 Variable Description Variables

Description

Cereal import dependency ratio

Cereal import dependency ratio =

Share of dietary energy supply derived through cereals

Prevalence of severe food insecurity in total population

Average dietary energy supply adequacy Wheat yield Per capita income

Incidence of caloric losses at retail Consumer price index value Political stability and absence of violence Source: www.fao.org.in

( Cereal import dependency ratio ) ´100 ( Ceereal production + Cereal imports ­ Cereal exports )

The indicator assumes only values of 100. Negative values indicate that the country is a net exporter of cereals. It highlights the energy supply (in kcal/caput/day) derived from cereals, roots, and tubers as a percentage of the total Dietary Energy Supply (DES) (in kcal/caput/day). The database used the FAOSTAT food balance sheets to retrieve country-wise respective data. As per FAO, ‘prevalence of severe food insecurity is an estimate of the percentage of people in the population who live in households classified as severely food insecure’. One-parameter logistic Item Response Theory model (the Rasch model) was used to estimate the probability to be food insecure. The FIES global reference scale was used for cross-country thresholds of comparison. The threshold to classify “severe” food insecurity indicates the item “having not eaten for an entire day” on the global FIES scale. The indicator expresses the Dietary Energy Supply (DES) as a percentage of the Average Dietary Energy Requirement (ADER). It is the ratio between productions to area under particular crop. GDP per capita in purchasing power parity (PPP) terms have been used as measure of per capita income. Data are in constant dollars prices with reference to 2011 level. Incidence of caloric losses at retail distribution level. Weighted average of consumer prices. It measures the ‘perceptions of the likelihood that the government will be destabilized or overthrown by unconstitutional or violent means, including politically-motivated violence and terrorism’.

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In this study, the prevalence of severe food insecurity along with share of dietary energy supply derived through cereals and cereal import dependency ratio is assumed as endogenous variable in the system of equation. The list of Z variable elements is described in Table 4.1. As endogeneity exists in the framed model, it is assumed that disturbances of the equations are correlated so that E(εε ¢) = S

(4.5)

And their expected value is zero. To solve the system of equation, the instruments are derived by linearly regressing all endogenous variables on exogenous variable X ( X ¢X ) X ¢zi "i ­1

(4.6)

different assumptive limitedness and computational difficulty. The major rigid assumption in linear regression framework is constant marginal effect of covari­ ates across the covariate space (Ferwerda et al., 2015). In addition, the construction of correct functional form is also difficult and, thus, misspecification may result in constructed econometric model leading to biased estimate (Hainmueller and Hazlett 2014). So, following Rifkin et al. (2003), Cawley and Talbot (2002), and Ferwerda et al. (2015), non-parametric Kernel-Based Regularized Least Squares (KRLS) framework was adopted to identify the factors impacting the prevalence of severe food insecurity, share of dietary energy supply derived through cereals, and cereal import dependency ratio (Eqs. (4.1)–(4.3)), assuming the target function as y = f ( x)

(4.7)

f ( x) = å iN=1 ci k ( x, xi )

(4.8)

And approximating it as

where k(x, x1) captures the similarity between (x), that is, point of interest and covari­ ate vector [Insert Equation Here] out of N vectors by assigning weight ci. Equations (4.1)–(4.3) were estimated using the KRLS framework, and reported results were presented in Table 4.2 along with 3SLS estimates for comparison.

4.3 Results and Discussion 4.3.1 Situation Assessment of Food and Nutritional Security: Worldwide Perspective It is evident from the results that, on average, 0 to 60% of the overall worldwide population still experiences acute food insecurity (Figure 4.2). However, the global

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Prevalance of severe food insecurity in total population Prevalence of undernourishment (percent) (3-year average) Percentage of stunted children who are under 5 years age Prevalence of anaemia in women in reporductive age (15-49 years)

FIGURE 4.2 Worldwide food and nutritional security scenario.

average of 7.58% indicates that there are comparably fewer people who experience extreme food insecurity. However, when expressed in absolute terms, it equates to 560 million people who are severely food insecure due to a lack of access to, avail­ ability of, or affordability of food. Country-wise prevalence of undernourishment was also found to be high with country-specific 2.5 to 59.5% of its undernourished population. The global average of 10.09% undernourishment with standard devia­ tion of 11.34 indicates quite large cross-country variations. Additionally, it was found that, on average, 15.13% children worldwide under the age of five suffered from stunting. For certain nations, the percentage is as high as 57.2%, although it is 0 for some nations. Further, it was observed that anaemia affects roughly 26% of women globally between 15 to 49 years of age and particularly during reproductive age. Surprisingly, the figure rose up to 61.5% for specific countries (Niger, Gabon, Nigeria, Senegal, Mali, etc.). Nonetheless, in developed countries like New Zealand, the United Kingdom, and France, the incidences of anaemia were very less.

4.3.2 Association Between Different Parameters of Food Security The association between different food and nutritional security parameters was further assessed to identify rank correlation and degree of association between the identified parameters (Table 4.2). Kendal Tau statistic revealed that there exists high rank order cor­ relation between undernourishment of population and percentage population of stunted children (tau = 0.579). Further, the prevalence of anaemia among women in reproductive age was also found to be highly associated with the percentage of undernourished popu­ lation in the country (0.460) and percentage of stunted children (tau = 0.499).

113

Contribution of Wheat in Global Food Security TABLE 4.2 Association Between Different Food and Nutritional Security Parameters Prevalence of Severe Food Insecurity in Total Population

Prevalence of Undernourishment

Percentage of Stunted Children

Prevalence of severe food insecurity in total population

1

Prevalence of undernourishment

0.177

1

(0.004) 0.291

0.579

1

(0.001) 0.138

(0.001) 0.460

0.499

(0.019)

(0.001)

(0.001)

Percentage of stunted children Prevalence of anaemia in women in reproductive age

Prevalence of Anaemia in Women in Reproductive Age

1

4.3.3 Role of Wheat in Food Security Wheat constitutes a significant portion in the food consumption basket of the majority of the population. It can meet the daily dietary energy requirement of the population with superior nutritive value (Shewry and Hey, 2015). Numerous studies have dem­ onstrated how important wheat is in reducing hunger and malnutrition. Wheat consti­ tutes a balanced diet comprising adequate quantity of quality carbohydrates, protein, fat and other micronutrients (Collins, 2007; Yonar et al., 2021). So, to estimate the role of wheat in determining food insecurity, a system of equa­ tion was framed (Eqs. (4.1)–(4.3)) and estimated using 3SLS framework (Table 4.3). The Kernel-Based Regularized Least Square technique provided estimates for mean population, first quartile (lower quartile), median population (50 percentile), and third quartile (upper quartile) (Table 4.3). According to the estimates, average dietary energy supply adequacy rate reduces food insecurity. It was also found that per capita income has a significant negative impact on food insecurity and it enhances food secu­ rity. Higher consumer price index has been found to worsen food security. The cereal import dependency ratio was found to positively affect the share of dietary energy supply derived from cereals. The countries importing wheat have a strong dependence on cereal in terms of eating habits (Kataki et al., 2001). Political instability had a considerable negative impact on food security. Further, it was observed that wheat yield of a particular country and the share of dietary energy sup­ ply derived through cereals describe its cereal import dependency ratio. The estimated model was tested for adequacy, and the overall model fit was found satisfactory (Table 4.4).

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TABLE 4.3 Estimates of Parameters Determining Food Insecurity, Dietary Energy Supply, and Cereal Import Coefficient z

Avg.

P25

P50

P75

0.069

−0.045 −0.014

0.001 −4.822 −0.232

0.001 0.001 −2.039 −0.612 0.431 1.025

0.007

0.057

−0.302

−0.202 −0.045

−0.069

−0.010 0.061

Ŷ = Prevalence of severe food insecurity Average dietary energy 0.025 0.920 −0.042* supply adequacy Wheat yield 0.001 0.630 0.001 Log (per capita income) −4.836*** −6.040 −2.712*** Incidence of caloric losses at −0.596 −0.670 0.297 retail Consumer price index value 0.061*** 4.150 0.067*** Intercept 43.119*** 5.51 Ŷ = Share of dietary energy supply derived through cereals Average dietary energy 0.126*** 4.160 −0.145*** supply adequacy Cereal import dependency 0.158*** 2.920 −0.007 ratio Political stability and −7.646*** −5.500 −7.430*** absence of violence Intercept 26.286*** 7.460 Ŷ = Cereal import dependency ratio Consumer price index value −0.091 −0.880 −1.010*** Wheat yield 0.001* −1.810 −0.001** Share of dietary energy supply 1.117* 1.870 1.309*** derived through cereals Log (per capita income) −3.752 −0.480 9.201 Intercept 24.760 0.270

0.114

−11.925 −7.884 −3.420

−1.781 −0.001 −0.028

−0.779 −0.071 −0.001 0.000 0.839 2.713

-−2.982

8.352

17.917

Note: *, **, *** indicates significance at 10%, 5% and 1% level respectively.

TABLE 4.4 Model Adequacy Test Model adequacy test Equation (4.1)

Equation (4.2)

Equation (4.3)

R square (3SLS)

0.34

0.12

0.05

Chi square R square (KRLS) Leave one out error loss

80.38*** 0.51 1202

58.46*** 0.62 1817

20.30*** 0.41 8602

Note: *, **, *** indicates significance at 10%, 5% and 1% level respectively.

The relation between wheat yield and food insecurity (the prevalence of severe food insecurity) was modelled using nonlinear and nonparametric regression using locally weighted scatterplot smoothing (LOWESS) estimator by computing an estimate of the location of wheat yield level (y) within a specific band of food insecurity level (x) (Cleveland, 1979).

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20

40

60

Contribution of Wheat in Global Food Security

8

9

10 log_yield

11

12

Prevalance of severe food insecurity in total population OLS fitted values

KRLS fitted values

FIGURE 4.3 LOWESS estimate of prevalence of severe food insecurity in total population with respect to wheat yield.

(x) = (y | x)

(4.9)

The estimated effect of wheat yield on food insecurity was found negative as indi­ cated by negative slope of the fitted line (Figure 4.3). In other words, we can say wheat yield has positively contributed towards food security. However, the slope of the fitted line derived through the estimates of Kernel-Based Regularized Least Square tech­ nique was found comparatively higher than the estimated fitted line derived through 3SLS. The better model fit in KRLS indicates the reason behind it (Rifkin et al., 2003; Cawley and Talbot, 2002; and Ferwerda et al., 2015).

4.3.4 Wheat Yield and Yield Gap Wheat yield was found to be highly region specific, and the variation across countries was found very high (Figure 4.4A). The worldwide average yield was estimated to be 3 tonnes/ha. For some regions, viz. Egypt, China, Mexico etc., wheat yield level was found higher than 5 tonnes/ha for specific year. Figure 4.4B depicts the yield gap in wheat across the wheat-growing countries. The distribution indicate that the modal yield gap in wheat is approximately 3 tonnes/ha. Further, the yield level of wheat was found positively dependent on time (t). Wheat yield is observed to be positively impacted by innovations and technology adoptions, as ‘t’ implies technological or institutional innovation. Further, the average tempera­ ture shift was also found to have a negative impact on yield level. Wheat yield level was observed to be significantly impacted by an increase in temperature (Figure 4.5).

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4 -0 0e 5.

4 -0 0e 5.

4 -0 0e 4.

4 -0 0e 4.

4 -0 0e 3.

4 -0 0e 3.

4 -0 0e 2.

4 -0 0e 2.

4 -0 0e 1.

4 -0 0e 1.

0

0

0

2000

4000

Density

6000

8000

10000

0

kdensity Wheat yield (kg/ha)

1000

2000

Density

(A)

3000

4000

kdensity Yield gap (kg/ha)

(B)

-2000 -4000 -8000

-10000

-6000

-5000

e( yield_gap | X )

0

0

2000

5000

FIGURE 4.4 (A) Yield distribution of wheat across the globe; (B) yield gap in wheat across the wheat-growing regions in the world.

-20

-10

0 10 e( time | X ) (time frame: 2000-2020)

coef = 22.917799, se = 5.92638, t = 3.87

20

-1 0 1 2 3 e( temperaturechangedegreecerlciuc | X ) coef = -1202.1216, se = 67.815112, t = -17.73

FIGURE 4.5 Effect of temporal and temperature component on the yield level of wheat.

4.4 Measures to Maintain and Enhance Wheat Yield 4.4.1 Varietal Improvement and Training – Institutional Support The adoption of proven agronomic and management practices helps in enhancing and sustaining wheat productivity. Government and Research and Development (R&D) organizations are promoting modern varieties of wheat – staple food crop for ensuring food security. A nationally representative of farm households’ data suggest that around three-fourth wheat pro­ ducers have adopted improved varieties of wheat accounting for 83% of total wheat area in the country. Large and medium farmers are typically the ones who are early adopter of improved varieties; these farmers benefit from higher pricing and better extension services than non-adopters. It is also important to know the characteristics

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of the households which act as push factors to adopt any new intervention. In this section, we have succinctly outlined the review of the previously completed research work. Improved wheat varieties have a considerable and favourable influence on food security in rural Ethiopia − a 1% increase in their area reduces consumption costs and increases food security by 2.9 and 45%, respectively. In major wheat-growing regions of Mebya district in Tanzania, the adopters preferred a wheat variety on the basis of primary characteristics such as high yield, marketability, grain colour, and early maturity. Moreover, farm size, family size, and the use of hired labour significantly affected the proportion of land allocated to improved wheat variet­ ies (Mwanga et al., 1999). In the same line, a cross-sectional study in Meket district of Amhara National Regional State in Ethiopia used 214 agricultural households which suggested that livestock number, assets ownership, access to extension services, and lit­ eracy considerably affect the adoption of improved wheat varieties (Siyum et al., 2022). In Hula Woreda of Ethiopia, a study of 124 randomly selected households identi­ fied the factors which influence the adoption of improved wheat varieties. The fac­ tors of household income, fertilizer use, and credit access influence such decisions significantly. The study ascertained the profitability of improved wheat varieties with the help of partial budgeting technique and showed their impact with the increase in the production of improved varieties and better income of the adopter farmers (Degu et  al., 2006). Matuschke et  al. (2007) assessed the adoption and impact of hybrid wheat in India using contingent valuation method and instrument variable approach. They found noteworthy yield and quality advantage over traditional varieties. The input intensity was also less in hybrid wheat and hence affordable to small farm­ ers. It provided greater economic benefits to smallholders as compared to their large counterparts. The small farmers gained more (₹2,048/acre) as compared to medium (₹1,924/acre) and large farmers (₹1,466/acre). The factors such as easy access to information and income can affect the adoption of hybrid wheat in the study area. A similar study by Tesfaye et al. (2016) in Ethiopia Arsi Zone used Propensity Score Matching method to recognize the impact of improved varieties of wheat on farm pro­ ductivity and income. The overall adoption rate was 56% in the study area. The results of probit model showed that the adoption of improved wheat varieties is much more likely in farms with the male head (decision-maker) of household, frequent occur­ rence of diseases on farms (traditionally growing varieties), and livestock ownership. Wheat yield was reported to be higher in case of adopters, and they also earn 35 to 50% higher income than non-adopters. Using Propensity score matching (PSM), Mulugeta and Hundie (2012) examined that technology advancements in wheat have a significant impact on daily food consumption per person in Southeast Ethiopia. The estimated Average Treatment Effect on the Treated (ATT) was found to range from 377.37 to 603.16 calories per day which signified that improved wheat technology dis­ semination has contributed towards food security of farm households.

4.4.2 Adoption and Impact of Improved Technologies (Including Biofortified Varieties) and Natural Resource Practices 4.4.2.1 Natural Resource Practices and Zero Tillage Conservation agriculture and zero-tillage techniques can aid to a greater extent in reducing the negative externalities – arising due to continuous rice–wheat cropping

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system in India. By using a displacement model, Krishna et al. (2022) revealed that the economic impact of technology is more pronounced in the state of Bihar (less developed) than that of Punjab (agriculturally developed state). A similar micro level study by Krishna and Veettil (2014) found that with the implementation of zero-tillage in wheat cultivation, costs were reduced by almost 14%, productivity increased by 5%, while technical efficiency climbed by 1%. Further, the resource use efficiency and the net returns were highest in zero tillage (ZT) in Faisalabad, Pakistan (Farooq and Nawaz, 2014). In a study conducted by Ladha et  al. (2009) on rice–wheat System across IndoGangetic Plains (IGP), the laser land levelling techniques increased farmers’ net income by 145–300 USD/ha. This is due to the improvement in wheat productivity by 7–20% and saving the irrigation water use by 10–25%. Sarwar and Goheer (2007) analysed the impact of zero tillage (ZT) practice on wheat crop in Sheikhupura district, Punjab (Pakistan). The yield from zero tillage (3.4 tons/ha) was considerably more than conventional techniques (CT) (3.1 tons/ha). The Benefit Cost Ratio (BCR) was also high for zero tillage (1.68) than conventional methods (1.12) as zero tillage is a natural practice and significantly decreases the working cost of cultivation. A  simi­ lar study done in Karnal district, Haryana (India), also reported higher yield and net returns from ZT over CT.

4.4.2.2 Biofortification Now as the world has achieved food security, accomplishing nutritional security is the new area of concern (Stein et al., 2007). The difference between ‘overt’ and ‘hidden’ hunger is highlighted in ‘United Nations Millennium Project Task Force on Hunger’ (Sanchez and Swaminathan, 2005). Besides, others suffer from hidden hunger owing to micronutrient and vitamin deficiencies such as vitamin-A-deficiency (150 million), iodine-deficiency (two billion), iron-deficiency (4–5 billion), and about 2.7 billion are zinc-deficient (2.7 billion) (World Health Organization, 2002). Biofortification – a breeding method with the potential to boost yield and improve mineral content (Welch and Graham, 2000) – could be a solution to alleviate hunger among the poor in a cost-effective manner. Since wheat is one of the world’s most important staples, feeding 35% of the population and serving around 20% of dietary energy, it can act as an affordable means of providing much-needed nutrition to dis­ advantaged sections in developing countries. In Southern Asia, Zn-fortified wheat led to an increase in Zn intake and reduction in child morbidity (Singh et al., 2017). First biofortified wheat variety (WB 02) developed in India, which is now cultivated in 1.44 lakh hectares, producing an economic surplus of ₹50.54 million (at 2011–12 constant prices). Despite its ability to eliminate hidden hunger and having potential economic benefits, the adoption rate is slow due to many socio-economic constraints and insti­ tutional bottlenecks (Cariappa et al., 2022). Stein et al. (2005) used disability-adjusted life years (DALYs) to assess the current burden of ZnD (zinc deficiency) and the potential impact (ex-ante) of biofortification. India loses 2.8 million DALYs annually as a result of ZnD. Zinc biofortification of the staples, i.e. wheat and rice, could reduce this burden by 20–51% and save 0.6–1.4 mil­ lion DALYs annually. According to WHO standards, the cost to prevent one DALY was to the tune of $0.73, the results demonstrating the cost-effectiveness of biofortification.

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Further, Stein et al. (2007) reported dual benefits (i.e. nutritional security and resource saving) of biofortified wheat. This hidden hunger, when left unchecked, results in child malnutrition. National Family Health Survey conducted in 2015–2016 across all dis­ tricts of India depicts that we, as a nation, rank first in terms of lower-than-normal birth weight of infants (44%), and around 36% of under five children are stunted. With staples having low Zn content, mild-to-moderate Zn deficiency is common in Indians. In one of the largest state of India, Uttar Pradesh, 48% under five children suffer from Zn deficiency. By using DALYs method, Tewari et al. (2017) reported that the current burden of ZnD (zinc deficiency) in Uttar Pradesh is 0.91 million DALYs. Among this, 0.89 million DALYs were lost due to mortality and 0.02 million DALYs were lost due to morbidity. They also compared the economics of traditional and biofortified wheat vari­ eties in which they found no noticeable difference among the cultivation cost and other factors such as taste, appearance, and cooking quality. They also reported that with the maximum adoption of Zn-fortified variety, that is, by 30%, the burden of ZnD will drop. They stated that the burden of ZnD will decrease by 11%, with 30% increase in the adoption of Zn-fortified varieties. The cost (₹79 to ₹177) of avoiding one DALY loss using Zn-fortified wheat is a promising means of ensuring the state’s nutritional security. Micronutrient deficits are quite common not only in India but also in China. According to a national census conducted in China, there are 250 million people who are iron-deficient, including 30% of children and 20% of women. About 100  mil­ lion people, mostly in rural regions, are affected by ZnD, which causes stunting (low height for age). To combat these deficiencies, several interventions were identified such as supplementation, dietary diversification, and food biofortification. According to Ma et al. (2008), the biofortification of staples such as wheat and rice exhibited the lowest per capita cost 0.01 I$ (international dollars) in addressing these deficiencies. Ex ante economic impact of wheat fortified with zinc was examined in blast-affected districts of Bangladesh by Mottaleb et al. (2019). The study predicted that 24% area will be under new biofortified variety (BARI Gom 33) with the adoption rate of 30% by 2027. The study finds considerable monetary gains with 5.2% higher yields than existing varieties. Net production gains from this new variety would be 135.6 thou­ sand metric tons between 2017 and 2030, which would be worth USD 20.4 million.

4.5 Conclusions and Policy Implications An attempt has been made to understand how wheat crop plays a vital role in miti­ gating food and nutritional insecurity. Recent reports show that there is prevalence of food insecurity, as 11% of world’s population is underfed. Nevertheless, wheat is one of the most essential foods in the world, providing 20% of dietary energy and feeding 35% of the world’s population. Tracing back to the problem of hunger and food security at global level, we developed a system of equations, viz., (i) prevalence of severe food insecurity, (ii) share of dietary energy supply derived through cere­ als, (iii) cereal import dependency ratio, and estimated using 3SLS framework. The estimated effect of wheat yield on food insecurity was found to be negative (results of 3SLS). In comparison to 3SLS, the estimations from the Kernel-Based Regularized Least Square technique were robust – confirming that wheat is positively contribut­ ing to food security. The other variables like political instability and consumer price had a considerable negative impact on food security. However, wheat faces significant

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obstacles, notably lower farm productivity in some countries. The worldwide average yield was estimated to be 3 tonnes/ha, while it was more than 5 tonnes/ha for some countries, indicating scope for productivity improvement in less endowed regions through technological interventions and appropriate policy support. Further, wheat yield level was observed to be significantly impacted by climatic variables (such as temperature). Mitigating the effects of extreme climatic temperature could shore up wheat productivity, contributing to fighting food insecurity at the global level. In this direction, a number of studies noted that biofortification, conservation techniques, and varietal development might all significantly and favourably impact food security. Finally, we can show a strong link between wheat productivity and food security at the global level. Nonetheless, climate-smart technological interventions to wheat production might significantly reduce food insecurity.

REFERENCES Brussaard, L., Caron, P., Campbell, B., Lipper, L., Mainka, S., Rabbinge, R., & Pulleman, M. (2010). Reconciling biodiversity conservation and food security: scientific challenges for a new agriculture. Current Opinion in Environmental Sustainability, 2(1–2), 34–42. Cariappa, A. G., Ramasundaram, P., Gupta, V., Gupta, O. P., Kumar, A., Singh, S.,  & Singh, G. P. (2022). Biofortification in wheat: research progress, potentia l impact, and policy imperatives. https://ssrn.com/abstract=4087960. Cawley, G. C.,  & Talbot, N. L. (2002). Improved sparse least-squares support vector machines. Neurocomputing, 48(1–4), 1025–1031. Cleveland, W. S. (1979). Robust locally weighted regression and smoothing scatterplots. Journal of the American Statistical Association, 74(368), 829–836. Collins, S. (2007). Treating severe acute malnutrition seriously. Archives of Disease in Childhood, 92(5), 453–461. Degu, G., Dadi, L., & Negatu, W. (2006). Adoption and impact of improved wheat tech­ nology: the case of Hula Woreda, Ethiopia. Ethiopian Journal of Development Research, 28(2), 1–29. Dillard, H. R. (2019). Global food and nutrition security: from challenges to solutions. Food Security, 11(1), 249–252. Esquinas-Alcázar, J. (2005). Protecting crop genetic diversity for food security: political, ethical and technical challenges. Nature Reviews Genetics, 6(12), 946–953. FAO (1983). World Food Security: A  Reappraisal of the Concepts and Approaches (Director Generals Report). Rome: FAO. FAO (2018). Save food: global initiative on food loss and waste reduction. Retrieved from www.fao.org/save-food/resources/keyfindings/en/. Accessed 28 June 2022. Farooq, M., & Nawaz, A. (2014). Weed dynamics and productivity of wheat in conventional and conservation rice-based cropping systems. Soil and Tillage Research, 141, 1–9. Ferwerda, B., Yang, E., Schedl, M.,  & Tkalcic, M. (2015). Personality traits predict music taxonomy preferences. In Proceedings of the 33rd Annual ACM Conference Extended Abstracts on Human Factors in Computing Systems (pp.  2241–2246), New York: ACM. Greene, W. H. (2018). Econometric Analysis/Limdep Users Manual. New York: Econometric Software. Hainmueller, J.,  & Hazlett, C. (2014). Kernel regularized least squares: Reducing mis­ specification bias with a flexible and interpretable machine learning approach. Political Analysis, 22(2), 143–168.

Contribution of Wheat in Global Food Security

121

Kataki, P. K., Hobbs, P., & Adhikary, B. (2001). The rice-wheat cropping system of South Asia: Trends, constraints and productivity—a prologue. Journal of Crop Production, 3(2), 1–26. Krishna, V. V., Keil, A., Jain, M., Zhou, W., Jose, M., Padmaja, S. S., Escoto, L. B., Jat, M. L., & Erenstein, O. (2022). Conservation agriculture benefits Indian farmers, but technology targeting needed for greater impacts. Frontiers in Agronomy, 24. Krishna, V. V., & Veettil, P. C. (2014). Productivity and efficiency impacts of conservation tillage in northwest Indo-Gangetic Plains. Agricultural Systems, 127, 126–138. Ladha, J. K., Kumar, V., Alam, M. M., Sharma, S., Gathala, M., Chandna, P., Saharawat, Y. S.,  & Balasubramanian, V. (2009). Integrating crop and resource management technologies for enhanced productivity, profitability, and sustainability of the ricewheat system in South Asia. Integrated Crop and Resource Management in the Rice–Wheat System of South Asia, 69–108. Ma, G., Jin, Y., Li, Y., Zhai, F., Kok, F. J., Jacobsen, E., & Yang, X. (2008). Iron and zinc deficiencies in China: what is a feasible and cost-effective strategy? Public Health Nutrition, 11(6), 632–638. Maslow, A., & Lewis, K. J. (1987). Maslow’s hierarchy of needs. Salenger Incorporated, 14(17), 987–990. Matuschke, I., Mishra, R. R., & Qaim, M. (2007). Adoption and impact of hybrid wheat in India. World Development, 35(8), 1422–1435. Mottaleb, K. A., Govindan, V., Singh, P. K., Sonder, K., He, X., Singh, R. P., Joshi, A. K., Barma, N. C., Kruseman, G., & Erenstein, O. (2019). Economic benefits of blast-resistant bioforti­ fied wheat in Bangladesh: the case of BARI Gom 33. Crop Protection, 123, 45–58. Mulugeta, T., & Hundie, B. (2012). Impacts of adoption of improved wheat technologies on households’ food consumption in southeastern Ethiopia (No. 1007–2016–79620). International Association of Agricultural Economists (IAAE). Mwanga, J., Mwangi, W. M., Verkuijl, H.,  & Mussei, A. (1999). Adoption of improved wheat technologies by small scale farmers in Mbeya district of southern highlands, Tanzania. Regional Wheat Workshop for Eastern, Central and Southern Africa, Stellenbosch, 14–18 September, p. 603. Rifkin, R., Yeo, G.,  & Poggio, T. (2003). Regularized least-squares classification. Nato Science Series Sub Series III Computer and Systems Sciences, 190, 131–154. Sanchez, P. A., & Swaminathan, M. S. (2005). Enhanced: cutting world hunger in half. Science, 307, 357–359. Sarwar, M. N., & Goheer, M. A. (2007). Adoption and impact of zero tillage technology for wheat in rice-wheat system—water and cost saving technology. A case study from Pakistan (Punjab). In International Forum on Water Environmental Governance in Asia (pp. 14–15). Princeton, NJ: Citeseer. Shewry, P. R., & Hey, S. J. (2015). The contribution of wheat to human diet and health. Food and Energy Security, 4(3), 178–202. Singh, R., Govindan, V.,  & Andersson, M. S. (2017). Zinc-biofortified Wheat: Harnessing Genetic Diversity for Improved Nutritional Quality (No. 2187–2019–666, Science Brief: Biofortification Series). Mexico: International Maize and Wheat Improvement Center. Siyum, N., Giziew, A.,  & Abebe, A. (2022). Factors influencing adoption of improved bread wheat technologies in Ethiopia: empirical evidence from Meket district. Heliyon, 8(2), e08876. Stein, A. J., Meenakshi, J. V., Qaim, M., Nestel, P., Sachdev, H. P. S.,  & Bhutta, Z. A. (2005). Analysing Health Benefits of Biofortified Staple Crops by Means of the Disability-Adjusted Life Years Approach: A Handbook Focusing on Iron, Zinc and Vitamin A (Technical Monograph No. 4). Washington, DC: HarvestPlus.

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Stein, A. J., Nestel, P., Meenakshi, J. V., Qaim, M., Sachdev, H. P. S.,  & Bhutta, Z. A. (2007). Plant breeding to control zinc deficiency in India: how cost-effective is bio­ fortification? Public Health Nutrition, 10(5), 492–501. Tesfaye, S., Bedada, B., & Mesay, Y. (2016). Impact of improved wheat technology adop­ tion on productivity and income in Ethiopia. African Crop Science Journal, 24(s1), 127–135. Tewari, H., Rani, R., Singh, H. P., Singh, R., & Singh, P. K. (2017). Comparative study of biofortified and non-biofortified wheat in Uttar Pradesh, India: combating nutri­ tional security through biofortification. International Journal of Agricultural and Statistical Sciences, 13(1), 365–370. United Nations. (1975). Report of the World Food Conference, Rome, 5–16 November 1974. New York: UN. von Braun, J., & Birner, R. (2017). Designing global governance for agricultural develop­ ment and food and nutrition security. Review of Development Economics, 21(2), 265–284. Welch, R. M., & Graham, R. D. (2000). A new paradigm for world agriculture: produc­ tive, sustainable, nutritious, healthful food systems. Food and Nutrition Bulletin, 21, 361–366. World Bank. (1986). Poverty and Hunger: Issues and Options for Food Security in Developing Countries. Washington, DC: World Bank. World Health Organization (WHO). (2002). The World Health Report. Geneva: WHO. Wossen, T., Berger, T., Haile, M. G., & Troost, C. (2018). Impacts of climate variability and food price volatility on household income and food security of farm households in East and West Africa. Agricultural Systems, 163, 7–15. Yonar, A., Yonar, H., Mishra, P., Kumari, B., Abotaleb, M., & Badr, A. (2021). Modeling and forecasting of wheat of South Asian region countries and role in food security. Advances in Computational Intelligence, 1(6), 1–8. Zellner, A.,  & Theil, H. (1992). Three-stage least squares: simultaneous estimation of simultaneous equations. In Henri Theil’s Contributions to Economics and Econometrics (pp. 147–178). Dordrecht: Springer. Ziervogel, G., Nyong, A., Osman, B., Conde, C., Cortés, S., & Downing, T. (2006). Climate Variability and Change: Implications for Household Food Security. Washington, DC: Assessment of Impacts and Adaptations to Climate Change (AIACC).

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Contribution of Wheat in Global Food Security APPENDIX 4.1 List of countries included in the study Afghanistan Albania Algeria American Samoa Andorra Angola Antigua and Barbuda Argentina

Bolivia Bosnia and Herzegovina Botswana

Cook Islands Costa Rica

Finland France

Iraq Ireland

Malaysia Maldives

Cote d’Ivoire

Israel

Mali

Brazil

Croatia

French Polynesia Gabon

Italy

Malta

Brunei Darussalam Bulgaria Burkina Faso

Cuba

Gambia

Jamaica

Cyprus Czechia

Georgia Germany

Japan Jordan

Marshall Islands Mauritania Mauritius

Burundi

Democratic People’s Republic of Korea Democratic Republic of the Congo Denmark Djibouti Dominica Dominican Republic

Ghana

Kazakhstan

Mexico

Greece

Kenya

Greenland Grenada Guatemala Guinea

Kiribati Kuwait Kyrgyzstan Lao

Micronesia (Federated States of) Mongolia Montenegro Morocco Mozambique

Ecuador Egypt El Salvador

Guinea-Bissau Latvia Guyana Lebanon Haiti Lesotho

Myanmar Namibia Nauru

Equatorial Guinea Eritrea

Honduras

Liberia

Nepal

Hungary

Libya

Netherlands

Estonia

Iceland

Lithuania

Eswatini Ethiopia Fiji

India Indonesia Iran

Luxembourg Madagascar Malawi

New Caledonia New Zealand Nicaragua Niger

Armenia

Cabo Verde

Australia Austria Azerbaijan Bahamas

Cambodia Cameroon Canada Central African Republic Chad Chile China, Hong Kong SAR China, Macao SAR China, mainland China, Taiwan Province Colombia Comoros Congo

Bahrain Bangladesh Barbados Belarus Belgium Belize Benin Bermuda Bhutan

Nigeria Niue North Macedonia

Saint Kitts and Switzerland Nevis Saint Lucia Syrian Arab Republic Saint Vincent Tajikistan and the Grenadines

Venezuela Viet Nam Yemen

(Continued)

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APPENDIX 4.1 (Continued) Norway Oman Pakistan Palau Palestine Panama

Samoa Sao Tome and Principe Saudi Arabia Senegal Serbia Seychelles

Thailand Timor-Leste

Papua New Guinea Paraguay Peru Philippines

Sierra Leone

Togo Tokelau Tonga Trinidad and Tobago Tunisia

Singapore Slovakia Slovenia

Türkiye Turkmenistan Tuvalu

Poland

Uganda

Portugal Puerto Rico

Solomon Islands Somalia South Africa

Qatar

South Sudan

Republic of Korea

Spain

Republic of Moldova

Sri Lanka

Romania Russian Federation Rwanda

Sudan Suriname

Ukraine United Arab Emirates The United Kingdom of Great Britain and Northern Ireland United Republic of Tanzania The United States of America Uruguay Uzbekistan

Sweden

Vanuatu

Zambia Zimbabwe

5 Nutritional Composition, Bioactive Compounds, and Phytochemicals of Wheat Grains Akhlash P. Singh CONTENTS 5.1 5.2

5.3

5.4

Introduction.................................................................................................... 126

Nutritional Components of Wheat Grain....................................................... 128

5.2.1 Carbohydrate ..................................................................................... 129

5.2.1.1 Digestible Carbohydrates................................................... 129

5.2.1.1.1 Starch .............................................................. 129

5.2.1.1.2 Monosaccharides, Disaccharides, and

Oligosaccharides ............................................. 130

5.2.1.2 Non-Digestive Carbohydrates............................................ 130

5.2.2 Proteins.............................................................................................. 131

5.2.3 Lipid................................................................................................... 133

Micronutrients in Wheat Grains .................................................................... 134

5.3.1 Vitamins ............................................................................................ 134

5.3.1.1 Water Soluble Vitamin B Complex.................................... 135

5.3.1.2 Thiamine (B1) .................................................................... 135

5.3.1.3 Riboflavin (B2)................................................................... 136

5.3.1.4 Niacin (B3)......................................................................... 136

5.3.1.5 Pantothenic Acid (B5)........................................................ 136

5.3.1.6 Pyridoxine (B6) ................................................................. 137

5.3.1.7 Biotin (B7) ......................................................................... 137

5.3.1.8 Folate (Vitamin 9).............................................................. 137

5.3.2 Fat-Soluble Vitamins ......................................................................... 138

5.3.2.1 Vitamin E (Tocotrienols) ................................................... 138

5.3.3 Betaine and Choline .......................................................................... 139

5.3.4 Minerals............................................................................................. 139

5.3.4.1 Phosphate (P) ..................................................................... 140

5.3.4.2 Iron (Fe) ............................................................................. 140

5.3.4.3 Potassium (K)..................................................................... 140

5.3.4.4 Zinc (Z) .............................................................................. 141

5.3.4.5 Selenium (Se) ..................................................................... 141

5.3.4.6 Manganese (Mn) ................................................................ 141

5.3.4.7 Copper (Cu)........................................................................ 142

Bioactive Phytochemicals .............................................................................. 142

5.4.1 Phytochemicals.................................................................................. 143

DOI: 10.1201/9781003307938-5

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Phenolic Compounds ......................................................... 143

5.4.1.1.1 Ferulic Acid .................................................... 145

5.4.1.1.2 Sinapic Acid .................................................... 146

5.4.1.1.3 P-Coumaric Acid ............................................ 146

5.4.1.1.4 Caffeic Acid .................................................... 146

5.4.2 Carotenoid ......................................................................................... 147

5.4.2.1 Lutein ................................................................................. 147

5.4.2.2 Zeaxanthin ......................................................................... 148

5.4.2.3 β-Cryptoxanthin................................................................. 149

5.4.3 Flavonoids.......................................................................................... 149

5.4.3.1 Flavan-3-ols........................................................................ 150

5.4.3.2 Flavonols ............................................................................ 150

5.4.3.3 Flavanones ......................................................................... 150

5.4.3.4 Flavones ............................................................................. 151

5.4.3.5 Isoflavones.......................................................................... 151

5.4.3.6 Anthocyanin....................................................................... 151

5.4.3.7 Proanthocyanidin ............................................................... 151

5.5 Benzoxazinoids (BXs).................................................................................... 152

5.6 Lignans........................................................................................................... 153

5.7 Alkylresorcinols............................................................................................. 153

5.8 Phytosterol...................................................................................................... 154

5.9 The Significance of Bioactive Compounds in Human Health....................... 155

5.9.1 Obesity and Weight Management ..................................................... 155

5.9.2 Metabolic Syndrome ......................................................................... 156

5.9.3 Cardiovascular Diseases (CVD)........................................................ 158

5.9.3.1 Hypertension ...................................................................... 158

5.9.3.2 Stroke ................................................................................. 160

5.9.4 Type II Diabetes ................................................................................ 160

5.9.5 Cancers .............................................................................................. 161

5.9.6 Effect on Overall Mortality............................................................... 162

5.10 Bioavailability and Bioaccessibility of Bioactive Compounds in Wheat

Grains ............................................................................................................. 163

5.10.1 Wheat Farming.................................................................................. 163

5.10.2 Germination....................................................................................... 164

5.10.3 Debranning ........................................................................................ 164

5.10.4 The Effect of Grain Milling and Grinding ....................................... 165

5.10.5 Bread Making.................................................................................... 166

5.10.6 Effect of Fermentation on the Whole Grain ..................................... 167

5.10.7 Enzyme Technology .......................................................................... 168

5.11 Conclusions and Prospects............................................................................. 169

Bibliography ............................................................................................................ 170

5.1 Introduction Wheat (Triticum aestivum L.) is a main food crop that provides nearly 20% of the total calories’ need to man every day. About 796 million tons of wheat grain were expected to be produced in 2023 a little bit higher of 2022’s wheat production, attributed to

Nutritional Composition of Wheat Grains

127

better climatic conditions (Angelino et  al., 2017; www.fao.org/worldfoodsituation/ csdb/en/2023). Currently, the human population is growing very fast. Therefore, it has become essential to enhance wheat crop production by nearly 60% to fulfill the food requirements by 2050 (www.fao.org/temprefdocrep/fao/meeting/018/k6021e.pdf). Wheat grain is a major source of carbohydrates and provides 55% of total carbohy­ drates obtained by food, so it offers humans most of the food calories (Liu, Yu, and Wu, 2020). The main wheat-cultivating countries are India, Russia, Ukraine, China, Turkey, Australia, the United States, and Pakistan. These countries collectively pro­ duce about 80% of the total wheat crop production world over. There are a few major world regions that consume most of the wheat grain in the form of different food items. These regions are West Asia, Western Europe, North Africa, sub-Saharan, Gulf countries, Egypt, South East Asia, China, and Mexico (I. Sharma, Tyagi, and Singh, 2015). In the last two decades, rapid urbanization and industrialization of cities have enhanced the demand for wheat as a major energy source in the world. Although a large number of ancient and newly developed wheat cultivars are available, only a few wheat species are mainly cultivated in the wheat-growing regions, such as Triticum aestivum, a hexaploid species also known as “common” or “bread” wheat. Another is T. turgidum var. durum, a tetraploid species that grows in hot, dry climatic conditions. Often, the “durum wheat variety” is used for mak­ ing pasta; therefore, this variety is also known as “pasta wheat”. There are many ancient wheat varieties, namely einkorn (diploid T. monococcum var. monococcum), emmer (tetraploid T. turgidum var. dicoccum), and spelt (T. aestivum var. spelta), which are known for their better protein quality, high level of bionutrients, and min­ eral content, and, thus, these varieties are gaining popularity in the current era too (Gałkowska, Witczak, and Witczak, 2021). There are a few wheat varieties that are not significant for crop production, but they are cultivated for cultural reasons in very small arable regions. Wheat grains are used by billions of people as staple diets in the form of chapati, pasta, bread, noodles, and other regional preparations around the world. It can be con­ verted into flour to make numerous food item, including bread slices, pasta, instant noodles, and other sundry food products. Wheat grains and their based foods have become very significant since the inception of agricultural societies (Hayakawa, Tanaka, Nakamura, and Endo, 2004). Therefore, wheat grain has emerged and will remain relevant because the wheat crop offers raw materials for the food and feed industry in the near future. Additionally, wheat grain is major source for energy, raw materials, bioactive, and nutritive components that are associated with health benefits for human populations all over the world. The bioactive and nutritive compounds are not evenly distributed in the wheat grains but rather unevenly distributed in the various fractions of the grain such as bran, germ, aleurone layers, and endosperm (see Figure 5.1). Wheat bran is an important provider of phytochemicals, especially phenolic acids (phenolics, carotenoids, flavonoids, alkylresorcinols, tocopherols, phytosterols, benzoxazinoids (BXs)), and other bioactive components and nutritive components, including water and fat-soluble vitamers, for example, vitamins E and its vitamers (Saini et  al., 2021). Many clinical and nutritional studies have proven that bioactive components present in whole wheat grains are effective against many lifestyle-related chronic diseases such as obesity, metabolic syndrome, cardiovascular diseases, diabetes mellitus, and cancers (Călinoiu and Vodnar, 2018). The potential effects of whole-grain-based diets against these diseases are endorsed by various

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human and animal-based experimental studies as well as World Health Organization (WHO) reports. Therefore, it is advised that the consumption of whole wheat grains is positively related to chronic diseases. It is well known that whole wheat grain diets contain many bioactive compounds, but their digestion and absorption and, thus, final bioavailability in the cellular systems/tissues, is the major issue (Angelino et al., 2017). Because the production of whole wheat grains and flour and different valueadded food items has undergone tremendous changes via many food-processing and manufacturing stages, the content of bioactive nutrients present in the cereal grains has substantially reduced. Many factors affect the direct and indirect bioavailability of grain-derived functional nutritive compounds in the human body, such as down­ stream processes, germination, farming, debranning, milling, and fermentation of wheat grains (Angelino et al., 2017). The main aims of this chapter are to describe the bioactive components, micronu­ trients, and macronutrients present in whole wheat grain and their potential benefi­ cial effects on chronic diseases that are known to damage human health substantially. Furthermore, current chapter also focuses on the numerous post-harvesting and foodprocessing methods that influence the bioaccessibility and bioavailability of bioac­ tive components, especially phenolic compounds, in the human digestive system. Finally, the current chapter encourages future studies on whole grains and their nutri­ tional advantages.

5.2 Nutritional Components of Wheat Grain Wheat is an inevitable part of a staple diet in the world because of its biochemical composition and balanced nutritive composition. Wheat grain provides most of the energy and nutrients for animals and the human population (Katileviciute et  al., 2019). The nutritional composition analysis of wheat grains is essential to test the efficacy of various crop improvement programs and to ensure the suitability of wheat grains for human consumption. Therefore, nutritional analysis is a very appropriate option employed in wheat crop production, which shows that wheat grains offer a balanced amalgam of macro and micronutrients for the human diet (Ma, Wang, Feng, and Xu, 2021). A common wheat grain proximate analysis shows that it con­ tains total carbohydrates, percentage of crude proteins, moisture, ether extract, crude fiber, and total ash (Table  5.1). It is well known that thousands of wheat varieties grow in the world, and their biochemical compositions are influenced by the types of varieties, cultivars, local growing conditions, application of fertilizers, and postharvest downstream processing. For example, normal bread and durum wheat grains have lower levels of bioactive and micronutrients than colored or pigmented wheat grains. Quantitative and qualitative data related to the protein in common wheat showed that almost 11 to 18% higher protein levels, 7.31 to 18.13% more essential amino acids, and 8.88 to 18.91% more amino acids are measured in the pigmented wheat species (Saini et al., 2021). The proximate composition is also employed for approximating the nutritive value of foods such as wheat, rice, pulses, and other food items by using various biochemical quantitative tests. Wheat is an important agricul­ tural commodity, and information related to the nutritive analysis of different wheat varieties is available in abundance, which shows that it offers a balanced diet in terms of proteins, fats, carbohydrates, dietary fiber, and minerals. The average values

129

Nutritional Composition of Wheat Grains TABLE 5.1 Comparison of Biochemical Composition (g/100 g) in the Wheat Grain Name of Species Common wheat (Triticum aestivum) Einkorn wheat (Triticum monococcum) Emmer wheat (Triticum dicoccon) Spelt wheat (Triticum spelta)

Total Carbohydrates

Crude Protein (N × 5.7)

Ether Extract

Dry Matter

Crude Fiber

Crude Ash

74.5

11.0

1.72

90.5

1.78

1.52

71.9

12.8

2.17

90.7

1.96

1.86

65.9

15.4

2.28

90.9

5.03

2.16

62,3

18.1

2.43

90.4

5.19

2.65

Note: Common wheat (Triticum aestivum), einkorn wheat (Triticum monococcum), emmer wheat (Triticum dicoccon), and spelt wheat (Triticum spelta) source (Biel et al., 2021).

of nutritional components are given in Table  5.1 (Biel, Jaroszewska, Stankowski, Sobolewska, and Kępińska-Pacelik, 2021), which shows a typical proximate analysis of a few wheat varieties.

5.2.1 Carbohydrate Wheat grain is the final product of wheat crop farming and harvesting. Many dietary carbohydrates are present in wheat grain, ranging from simple sugars to non-digestible complex polysaccharides, including both digestible and resistant starch, glucans, and lignin. Furthermore, wheat grain also contains smaller and lower molecular weight compounds such as monosaccharides, disaccharides, and oligosaccharides (Lineback and Rasper, 1988). Each type of carbohydrate requires different levels of digestion and metabolism in the human body, hence their bioavailability and bioaccessibility are major issues that will be discussed in the later part of this chapter. The total car­ bohydrates present in whole wheat grain can broadly be classified into two groups, for example, digestible and non-digestible.

5.2.1.1 Digestible Carbohydrates Wheat grains consist of carbohydrates that can be digested in the mouth and gut called “digestible carbohydrates”, for example, starch and many sugars.

5.2.1.1.1 Starch Wheat grains are major sources of starch, a main dietary carbohydrate that provides a big chunk of cellular fuel responsible for energy production in cellular respiration. At the time of maturity, wheat grain consists of a total of 85% (w/w) carbohydrates, mainly comprising starch. Starch is mainly present in the endosperm part and is a major fraction of the whole grain (D’Appolonia and Rayas-Duarte, 1994a; Gooding

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and Shewry, 2022). Starch is a primary source of energy and is eaten in the form of mainly chapati, bread, and other wheat-based food items all over the globe. The starch consists of two types of glucose-based polymers that are amylose and amylopectin in a 1:3 ratio in most wheat varieties. The amylose is a single long unbranched chain of many thousands of glucose residues linked via 1–4 glycosidic bonds. While amylopectin is an intensely branched polymer containing hundreds of glucose residues joined together by 1–6 glycosidic linkages, and overall, both poly­ mers constitute starch, which has 100,000 glucose unit residues arranged in a highly intricate branching polymer that is further aggregated to form characteristic starch granules in wheat grain (Shevkani, Singh, and Bajaj, 2017).

5.2.1.1.2 Monosaccharides, Disaccharides, and Oligosaccharides In addition to high molecular weight polysaccharides, wheat grain also comprises low molecular weight monosaccharides (glucose), disaccharides, and oligosaccha­ rides, which constitute approximately 7% of the total carbohydrates of wheat grain. These sugars mainly present in the different fractions of wheat grain, for example, aleurone, endosperm, and embryonic tissues. Fructans is another important sugar present in the starchy endosperm and bran, which are two major parts of the whole grain (Shevkani et al., 2017).

5.2.1.2 Non-Digestive Carbohydrates Non-digestible carbohydrates are another category of carbohydrates provided by the wheat grains, for example, resistant starches (RSS), chemically modified starches, complex non-starchy polysaccharides, and cell wall polysaccharides. Among them, resistance starch is very significant and constitutes the major chunk of dietary fiber. Resistant starch is not digested by gut enzymes due to its entrapment in the food structure. This can be further divided into five different categories, that is, ranging from RS 1 to RS5 types. Generally, the resistance characteristic of starch in the diges­ tion system is mainly inferred by the size, shape, composition, and crystal structure of starch granules. Furthermore, the characteristics of starch resistance are influenced by the composition of amylose and amylopectin, proteins, lipid-based compounds, and phosphate ions present in the grain (D’Appolonia and Rayas-Duarte, 1994b). Resistant starch is part of dietary fiber and has the same properties as the non-starchy polysaccharides (NSP), which are fermented by gut microorganisms and metabolized into short chain fatty acids (SCFAs), for instance, acetate, butyrate, and propionate. These metabolites are highly significant for human and animal metabolisms. Whole­ grain bread is the major source of dietary fiber (Ferguson and Harris, 1999; Niba and Niba, 2003). Currently, dietary fiber is considered to be a major agent that protects the human population from many types of chronic diseases such as diabetes, heart diseases, and cancer of the large intestine. In addition to resistant starch, cell-wall-based polysaccharides are also the major part of grain dietary fiber. Cell wall polysaccharides are about 12% and are mainly present in all tissues of wheat plants. These polysaccharides are conjugated with other components like proteins, ions, and other branched polymers of plant cells and make an intricate interwoven network of dietary fiber. Hence, dietary fiber is resilient to digestion process in the gut. The major cell wall-based polysaccharides are cellulose,

Nutritional Composition of Wheat Grains

131

lignin, pectin, fructans, and dimers of ferulic acid and other polysaccharides. The other cell wall polysaccharides of the wheat grain are arabinoxylan and β-D-glucan, which contain a cellulose-like structure and are also known as wheat bran β-glucan. Additionally, cell wall polysaccharide also contains small amounts of cellulose ((1→4)-β-D-glucan), glucomannan, callose ((1→3)-β-D-glucan), xyloglucan, and pec­ tins. Lignin is also an important cell wall glucan consisting of monomeric units of aromatic alcohols. Lignin is mainly present in the pericarp/seed coat of a whole grain, which makes bran fraction a rich source of dietary fiber, but it is generally not present in white flour (Parker, Ng, and Waldron, 2005). The total dietary fiber is classified into two main classes based on its water-binding capacities inside the human gut. First is soluble dietary fiber (SDF), which is soluble in water and mainly presents in bran which accounts for 82% of total soluble dietary fiber. Grain analysis shows that about 6.5 to 52.4 g/100 g of dry weight, dietary fiber has been quantified in the wheat bran (Liu et al., 2020). While the amount of dietary fiber in the grain part is about 11.6 to 17.0 g per 100 g of DM, which is substantially lower than the bran fraction (Liu et al., 2020). Second, the insoluble dietary fiber, which is not soluble in water, includes fructans, cellulose, arabinoxylan, and lignin. The amounts of insoluble dietary fiber are highly variable in terms of amounts among the various wheat varieties. DFs from wheat bran can influence the growth of specific bacteria, which often promotes the growth of SAFCs forming bacteria. These microbes produce specific types of metabolites via fermentation that further promote the growth of mucus-producing bacteria. Mucusproducing bacteria improve the intestinal barrier and regulate the function of the host immune system (Yao, Gong, Li, Hu, and You, 2022). Many scientific investigations have shown that gut bacteria also reduce inflammation by reducing cytokine levels.

5.2.2 Proteins Grain protein is classified as a macronutrient and, thus, somehow, fulfills protein require­ ments in wheat-consuming population. In most wheat varieties, the amount of protein varies from 10 to15% of the dry weight and is distributed unevenly in various parts of the grain. For example, protein content in the various parts of grain was 5.1%, 5.7 %, 22.8%, and 34.1% in pericarp, testa, aleurone, and germ, respectively (Shewry and Hey, 2015). It is noticeable that the protein quantity of the wheat grain composition is influenced by both genetic and environmental factors, for example, the types of cultivars and especially the application of nitrogen fertilizers. Generally, quality of wheat protein is mainly determined by the content of essential amino acids. Because a complete stan­ dard set of 20 amino acids is not produced by human cells, essential amino acids must be added to the human diet. Being a cereal, wheat often lacks lysine amino acid, but the rest of the other necessary amino acids are present in sufficient quantities (El-Naggar, de Neergaard, and El-Araby, 2009). So, wheat grain can be considered a good source of protein. Wheat grain possesses a unique amino acid profile, characterized by a high content of glutamine and proline residues and a lower lysine concentration. Wheat grain also expressed highly specific protein profiles, including water-soluble albumins, globulins, gliadins, and glutenin. Among them, two proteins, albumin and globulin, account for 20 to 25% of the whole proteins present in grain, which are mainly present in the endosperm fraction of grain. Both water-soluble albumin and globulin are responsible for enhancing the biological value of cereal protein, which is

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FIGURE 5.1 The histological structure of a single whole wheat grain is partitioned into three impor­ tant fractions that are endosperm, germ, and bran. The bran part is further divided into many layers.

known as superior nutritional indicator (Merlino, Leroy, Chambon, and Branlard, 2009). Moreover, both albumin and globulin fractions indirectly influence the breadproducing process because both are important for the normal baking properties of bread. Albumins and globulins contain more necessary amino acids in comparison to both glutenin and gliadin, such as arginine, aspartic acid, lysine, threonine, and tryptophan amino acids. Wheat gluten, a complex protein composed of glutenin and gliadin, also known collectively as gluten proteins, accounts for 63–90% of total grain proteins. Two pro­ teins gliadin and glutenin are crucial for the bread production qualities of wheatbased flour because both proteins are important for water and gas retention at the time of bread and chapati preparation (Mills et al., 2020). Therefore, they determine the physio-chemical properties of wheat-based food products, including many bread qualities. Moreover, aforementioned proteins create a continuous, cohesive network that encircles the starch molecules, which is very crucial for dough formation and bread quality because it influences loaf area, breadcrumbs, and the overall texture of the bread (Brouns et al., 2022). In some rare health conditions, the consumption of wheat seed proteins can cause a variety of immunological diseases, such as gluten-sensitive enteropathy, also known as celiac disease (CD), allergy and asthma, and wheat-dependent exercise-induced anaphylaxis (WDEIA) in genetically susceptible people (Wieser, Koehler, and Scherf, 2020). Globulin was the first storage protein discovered in wheat that was found to cause diabetes (T1D) and celiac disease simultaneously. Likewise, gliadins, a fraction of gluten, are known to have epitopes that elicit immune responses and cause celiac disease. The main reason for the development of CD is that gliadin cannot be digested in the gastrointestinal tract due to its unique sequence of amino acids that are not acted upon by enzymes (Wieser et  al., 2020). Therefore, partially digested peptides can elicit an innate immune response by physically interacting with the small intestine mucosa and causing the CD.

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Nutritional Composition of Wheat Grains

5.2.3 Lipid Wheat grain is not a good source of fat in the human diet and only contains about 2.2% of its dry weight. Wheat fatty acids can be divided into various groups based on their nutritional values. For example, wheat grains contain 1.4 g of saturated fatty acids/100 g of dry weight, 1.1 g of monounsaturated fatty acids/100 g of dry weight, and 4.3 g of polyunsaturated fatty acid/100 g of dry weight (Boukid, Folloni, Ranieri, and Vittadini, 2018). Although wheat lipids do not contribute nutritionally, their interactions with protein and carbohydrates impart texture and quality to bread and wheat-based food. In wheat grain, fatty acids are available in the form of triacyl glycerols (TAGs). On the other hand, bound-form fatty acids are present in the form of phosphatidylcho­ line, phosphatidyl ethanolamine, and phosphatidyl serine, as well as lysophosphatidyl derivatives. Many biochemical analyses show that wheat grain comprises a substantial amount of unsaturated fatty acids, for example, oleic, linoleic, and α-linoleic acids. Recently, studies on hamsters indicate that wheat bran oil (WBO) is equally significant as rice bran oil (RBO) by inhibiting both cholesterol and fatty acid synthesis inside the liver by decreasing the activities of hepatic 3-hydroxy-3-methylglutaryl-CoA reductase and fatty acid synthase enzymes. This suggests that wheat bran oil can replace rice bran oil in the human diet (Lei, Chen, Liu, Wang, and Zhao, 2018). So far, the aforementioned discussion was based on the whole grain, but the total nutri­ ents in wheat grain are divided into the various fractions of wheat grain, which are men­ tioned later in the chapter. Commercially, wheat kernels undergo many industrial and downstream processes that give rise to many food products. The complete wheat kernel can be processed into bran, germ, refined flour, and whole-grain flour-based food items that contain an uneven distribution of nutrients and bioactive components (Katileviciute et al., 2019). Table 5.2 shows the presence of the bionutrients distributed in the different TABLE 5.2 Comparison of Nutritional Contents Extracted from Different Parts of the Whole Grain and Refined Flour in Wheat (µg/100 g) Content

Aleurone

Bran

Germ

Carbohydrates Proteins Fats DF Thiamine 1 Riboflavin 2 Niacin Pyridoxine 6 Folates Iron Zinc Magnesium Sodium β-Glucan

23 23 23.6 1.4 .2 32.9 1.3 .2 26 14 1.2 -

64.5 15.5 4.25 42.5 .523 .577 13.5 1.303 79 10.57 7.27 611 2 3

51.3 28.1 9.6 12.3 1.45 .61 1.42 5 17.8 259 5.5 -

Source: (Balandrán-Quintana et al., 2015; Cheng et al., 2022)

Whole Wheat Grain

White Wheat Flour

62.2 10 2 11 .4 .15 5.7 .35 37 4 2.9 124 5 .7

71 12.6 1.1 4 .07 .04 1 .12 22 .8 .64 20 2 .08

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parts of wheat grain. Therefore, it becomes essential to discuss various parts/fractions of the grain and their nutritive values, which are currently exploited in the protection of many chronic ailments such as cancers, diabetes, and cardiovascular diseases. Structurally, a complete wheat kernel can be divided into endosperm, bran, and germ (Figure 5.1). 1. Endosperm: The most of the starch and proteins exist in the endosperm which constitutes nearly 80–85% of the grain. The endosperm is wrapped in numerous outer layers, also referred to as the aleurone part. The aleurone contains living cells that are very rich in bioactive substances with proteins, arabinoxylans, and β-glucans specifically present in the cell wall. 2. Bran: The wheat bran contains pericarp and testa, which are about 13–17% of the whole grain. The testa is a cuticular part that is lignin-rich, waterinsoluble, characterized by alkylresorcinols, lipid-rich compounds that occur in the cuticle of grain. The grain pericarp constitutes the outermost layers of the whole grain, which is further classified into inner pericarp, outer pericarp testa, hyaline layer, and endocarp layers. 3. Wheat germ (WG): Wheat germ makes up 2–3% of the grain and includes the embryo and the scutellum. Both parts of the embryo and the scutellum are isolated by aleurone from the endosperm. The scutellum part of the grain is considered a storage region that lies between the pericarp and the embryo (Boukid et al., 2018; Panato, Antonini, Bortolotti, and Ninfali, 2017; Turnbull and Rahman, 2002). During the milling process of grain, the scutellum is excluded, and the germ is retained as an embryo.

5.3 Micronutrients in Wheat Grains Micronutrients are required for growth and development of the human body and thus need to be included sufficiently in the human diet. The deficiency of micronutrients is the major nutritional problem in the world, particularly in developing nations where children and women do not get the daily recommended amount (RDA) of vitamins. Generally, vitamins are produced by human cells, while plants and microorganisms can synthesize a complete spectrum of water-soluble vitamins. Micronutrients have a high level of modulatory effects on the biochemical reactions inside the cell, espe­ cially in the human context (Xu, An, Li, and Xu, 2011a). For instance, many coenzy­ matic forms of vitamins and metal ions act as coenzymes and cofactors, respectively, in enzyme-mediated biochemical reactions. Micronutrients also act as antioxidant agents against oxidation of biomolecules caused by reactive oxygen species (ROS) attributed to an oxidative environment in a cellular milieu. Generally, micronutrients are mostly vitamins and minerals (Hu and Schmidhalter, 2001). Vitamins are divided into two categories: water-soluble and fat-soluble vitamins. Most vitamins are present in whole wheat grains.

5.3.1 Vitamins Vitamins contribute significantly to maintaining a good health in animals and humans as well. They are required in minute quantities in the human diet every day. Whole

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grains provide most of the water and fat-soluble vitamins. Water-soluble vitamins include vitamins-B (B1 thiamine), B2 (riboflavin), B3 (niacin), B6 (pyridoxine), B9 (folate), and vitamin E (tocopherol/tocotrienol). In addition to B-complex vitamins, humans also require fat-soluble vitamins in a minute quantity for vital biochemical reactions, for example, vision, blood clotting, and reproduction. There are a few lipidsoluble vitamins like provitamin A (β-carotene), vitamin D (calciferol), and vitamin K (phylloquinone) occurring in whole wheat grains (Dhua, Kumar, Kumar, Singh, and Sharanagat, 2021; Shewry et al., 2011).

5.3.1.1 Water-Soluble Vitamin B Complex Many vitamins which belong to the B-complex are present in wheat grain, such as thiamine, riboflavin, pyridoxine, niacin, pantothenic acid, biotin, and folates. In most cases, vitamins are generally present in a group of whole grains. These vitamin mol­ ecules are water-soluble, a common feature among them, but otherwise they play highly diverse biochemical roles, particularly in the carbohydrates’ metabolism (thia­ mine), and proteins, and fats (riboflavin and pyridoxine), and folates in iron metabo­ lism. Vitamins are mainly available in the bran and germ fractions of the grain, for instance, aleurone layer. Cereals and cereal-based products provide around 30% of the daily need of vitamins in the diet. Many factors affect the availability of vitamins in wheat-based foods, for example, wheat varieties, growing location, use of manure, fer­ tilizers or herbicides, storage conditions, milling process, and bread making (Heshe, Haki, Woldegiorgis, and Gemede, 2016). This fact is endorsed by the experiment conducted on whole meal flours of 24 winter wheat varieties grown in four differ­ ent locations, that is, the United Kingdom, Poland, France, and Hungary. Two spring varieties were grown on the same sites, and the total contents of thiamine, riboflavin, pyridoxine and the biological form of niacin (B3) were quantified. The values of B1 (5.53 to 13.55 g/g DW), B2 (0.77 to 1.40 g/g DW), and B6 (1.27 to 2.97 g/g DW) were in complete agreement with earlier reports. The milling process significantly reduced the number of vitamins, by about 68% of the total thiamine, 58.65% of the riboflavin, and 85% of the pyridoxine (Shewry et al., 2011). It would be noteworthy here that the use of natural manure increases the B vitamins, while the application of fertilizers or herbicides reduces the riboflavin concentration in wheat crops.

5.3.1.2 Thiamine (B1) Wheat grains and its based food products are the main sources of vitamin B1 or thiamine. Hence, it is recommended that there should be the inclusion of whole wheat grains and bran in human and animal diets because the outer coat of the seed is very rich in thiamine. In the case of wheat grain, thiamine is mainly present in the scutel­ lum in the free form. Thiamine pyrophosphate (TPP) is a coenzymatic active form of thiamine that mainly participates in carbohydrate metabolism. The deficiency of thiamine in the diet promotes body fat accumulation that is ascribed to the diver­ sion of excessive carbohydrates toward fat biosynthesis due to sluggish carbohydrate metabolism, including glycolysis and TCA (Goyer, 2010). Hence, the deficiency of thiamine promotes obesity, metabolic syndrome, and CVD. Beriberi is the main dis­ ease that has been documented in human subjects who have a deficiency of thiamine. In the biochemical analysis of several wheat genotypes (among them, 46 bread wheat,

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1 durum bread, and 2 spelt), the average value of thiamine was 3.82 g/g dry matter (DM), which was mainly reduced due to the fine grinding and milling process of whole grains (Batifoulier, Verny, Chanliaud, Rémésy, and Demigné, 2006).

5.3.1.3 Riboflavin (B2) Wheat grain consists of riboflavin, a vitamin that plays a very significant role in cel­ lular metabolism, particularly the metabolism of carbohydrates and proteins. There are two coenzymatic forms of riboflavin: (1) flavin adenine dinucleotide (FAD) and (2) flavin mononucleotide (FMN). Both of these forms act as intermediates of hydrogen donors and acceptors in the electron transport chain (ETC), where electrons travel through various proteins in cellular respiration, which is catalyzed by a plethora of mitochondrial enzymes. Although dairy products are a very rich source of riboflavin, whole wheat grain is provider of riboflavin; especially, bran fraction offers up to 20% riboflavin in the daily intake (Hrubša et  al., 2022; Thakur, Tomar, Singh, Mandal, and Arora, 2017). The average riboflavin value recorded in the wheat grain was 0.73 g per 100 DM, with a range of 0.48 g per 100 DM (‘Victo’ cultivar) to 1.07 g per 100 DM (blue cultivar ‘Meropa’). Genetic variability, down processing, and milling pro­ cesses are a few factors that substantially influence the availability of riboflavin in diets (Shewry et al., 2011). The deficiency of riboflavin can affect lipid peroxidation and oxidative stress inside the cell. Hence, the proper intake of riboflavin reduces the occurrence of some cancers, and it is also implicated in some neurological disorders.

5.3.1.4 Niacin (B3) Niacin, or nicotinic acid, is widely distributed in plants and animals. Whole cereals and wheat grains comprise a high amount of niacin. Biochemically, niacin is known as nicotinic acid (pyridine-3-carboxylic acid), and its biologically active form is nic­ otinamide and its derivatives. In humans, niacin is synthesized in the hepatocytes from tryptophan, an aromatic amino acid. Niacin has two most important coenzy­ matic forms, namely NAD(H) (nicotinamide adenine dinucleotide) and NADP(H) (nicotinamide adenine dinucleotide phosphate), which involve nearly 200 different metabolic reactions, particularly oxidation and reduction reactions in which electrons are accepted and donated, especially in the case of glycolysis and the TCA cycle. Persistent deficiency of niacin can lead to dyslipidemia and atherosclerosis in humans. Furthermore, NADPH indirectly protects the cell from oxidative stress via reducing the enzyme glutathione reductase, which requires the regeneration of GSH to act as an antioxidant against ROS and LDL oxidation (Ganji, Kamanna, and Kashyap, 2003; Garg et al., 2017). In a very significant experiment, the bioavailability of niacin was estimated in 24 wheat varieties that are grown at various locations in four countries. The average amount of niacin was measured at about 0.161.74 μg/g DW. Niacin is mainly concentrated in the bran and/or germ, but downstream processes such as mill­ ing degrade up to 68% of the total amount of this vitamin (Batifoulier et al., 2006).

5.3.1.5 Pantothenic Acid (B5) Pantothenic acid is a major water-soluble vitamin that is related to the vitamin B-complex. This vitamin is mainly synthesized in plants and is never present in

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human tissues. But whole grains and whole-grain-based diets are rich sources of pantothenic acid, especially in the brain, which is the major site of its occurrence. Pantothenic acid is the main precursor of the most important biomolecules that play a central role in the synthesis of central metabolites like acetyl CoA and an acyl carrier protein (ACP). Both metabolites, acetyl CoA and an acyl carrier protein (ACP), are involved in the oxidative metabolism of carbohydrates, transfer reactions in the citric acid cycle, and fat metabolism. It is already mentioned that glutathione dehydrogenase (GDH) acts as an antioxidant agent, and its production is promoted by pantothenic acid. The deficiency of B5 causes fatigue, sleep apnea, a weak digestive process, and neurol disorders (Tahiliani and Beinlich, 1991). The average amount of B5 in whole wheat ranged from 2.128 (emmer wheat grass) to 10.294 μg per gram of dry weight. In whole grains, average B5 content was recorded ranging from 3.296 to 10.294 μg per gram of dry weight in einkorn (IZA), emmer, durum, and bread wheat varieties (Pehlivan Karakas, Keskin, Agil, and Zencirci, 2021).

5.3.1.6 Pyridoxine (B6) Pyridoxine, or vitamin B6, is collectively used for three related compounds, namely pyridoxine, pyridoxal, and pyridoxamine. It mainly occurs in plant-based foods, espe­ cially wheat grain and wheat grain foods, which are considered excellent sources of vitamin B6. In the wheat grain, pyridoxine is present in the aleurone layer and germ. Pyridoxal phosphate (PLP) is the main coenzymatic form of pyridoxine that par­ ticularly contributes to protein metabolism in transamination, decarboxylation, and racemization reactions. PLP also plays a crucial role in the synthesis of many vital biochemicals, such as serotonin, histamine, and niacin, from amino acids (Mateo Anson, Hemery, Bast, and Haenen, 2012). The average value of pyridoxine was 2.2 g per 100 DM, with a range of 1.45 to 3.16 g per 100 DM in different wheat cultivars (Mateo Anson et al., 2012).

5.3.1.7 Biotin (B7) Biotin is also known as vitamin H, and it is mainly present in the free or bound form in wheat grain. Biotin is a heterocyclic sulfur-containing monocarboxylic with imidazole and thiophene rings, mainly attached to protein lysyl residues (biocytin) (McMahon, 2002). Normally, 11 μg/100 and 10.7 μg/100 biotin are present in whole grains and wheat flour, respectively, which may be present in free or conjugated form (Bryden, Mollah, and Gill, 1991). The milling process substantially reduces up to 70% to 80% of the biotin content present in whole cereals such as wheat, rice, rye, and maize. Biotin is very crucial in fatty acid metabolism and acts as a coenzyme for the enzyme acetyl-CoA carboxylase that catalyzes the carboxylation reactions, an initial step in fat biosynthesis. Biotin deficiency can lead to a loss of appetite and dermatitis in humans. The deficiency of biotin generally influence the transcription of genes that further affect pro-inflammatory processes like NF-kB (McMahon, 2002).

5.3.1.8 Folate (Vitamin 9) Folates are classified under the vitamin B complex. It is also named as vitamin B9 and includes tetrahydrofolate and its derivatives (collectively termed folates), which are

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considered essential micronutrients for human health due to their not being synthe­ sized in human cells. Often, 400 μg of folate is recommended for daily consumption, while pregnant women need 600 μg. Mostly, folates exist in reduced forms (tetrahy­ drofolate) rather than as folic acid (pteroylmonoglutamic acid) in whole wheat grain. Folates are essential micronutrients for humans and participate in many metabolic processes. In particular, folates play an important role in the one-carbon metabo­ lism. There are many forms of folate, but 5-methyltetrahydrofolate is a biologically active form that often participates in metabolic pathways. Folates act as the main donors of one-carbon units and contribute mainly to many biochemical processes that require single-carbon transfer, including purine biosynthesis and thymidylate. It also participates in the synthesis of methionine, serine, pantothenate, and trans­ fer RNA. Moreover, folate also provides methyl groups to the cellular methylation process. Furthermore, folates also participate in scavenging activities such as the removal of free radicals, as proven by many in vitro models. Indirectly, they also help in the reduction of homocysteine (Ohrvik and Witthoft, 2011; Stanger et al., 2009). Wheat contains a small amount of folate, ranging from 30.58 to 40.11 μg/100 g in whole grains, while in flour it was in the range of 9.29 to 10.64 μg/100 g. It is reduced significantly under various processing methods, such as storage (26%), milling (71%), boiling (13%), and baking (16%). These methods reduce the folate content in wheat and wheat products, while yeast-based fermentation improves the folate content in foods (Liang, Wang, Shariful, Ye, and Zhang, 2020).

5.3.2 Fat-Soluble Vitamins Many vitamins are soluble in fat and organic solvents but insoluble in water. Lipid or fat-soluble vitamins are present in various foods, including whole wheat grains. Vitamins like A, D, E, and K and their vitamers are classified as fat-soluble vitamins. Fat-soluble vitamins are used in diets, cosmetics, pharma, and healthcare products (Borel and Desmarchelier, 2018).

5.3.2.1 Vitamin E (Tocotrienols) Vitamin E is a lipid-soluble vitamin that acts as the most active antioxidant available in nature. This vitamin possesses the biochemical activity of α-tocopherol. Generally, Vitamin E includes a group of different eight vitamers: four types of tocopherols (α, β, γ, and δ) and four different corresponding tocotrienols (α, β, γ, and δ), and these vitamers are not chemically identical (Jensen and Lauridsen, 2007). The α- and γ-tocopherol forms are mainly present in bound form with transporting proteins and are also present in the hepatocytes due to their excessive involvement in metabolic reactions. However, the precise mechanism of action is not known, but experimental results show that vitamin E plays a protective role against ROS produced during low-LDL and PUFA oxidation, cancer, and cardiovascular diseases (CVD). The anti­ oxidant potential of vitamin E is attributed to its refined phenolic chromanol head group that is associated with plasma membrane (Azzi, 2007). Because α-tocopherol is preferentially maintained in the plasma membrane and reduces the concentration of peroxyl radicals, hence, vitamin E is also known as a very strong chain-breaking antioxidant and is actively involved in scavenging properties against ROS and other RNS. Vitamin E protects the plasma membrane and ultimately protects the RBC

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from hemolysis. Currently, the supercritical fluid extraction (SFE) process is com­ bined with carbon dioxide (SFE-CO2) for the extraction of vitamin E from wheat germ, which is considered a best source of vitamin E (T. Wang and Johnson, 2001) and contains about (α-tocopherol 1159 μg/g dry wt.) which is a substantially higher amount than that present in different parts of wheat grain (Capitani, Mateo, and Nolasco, 2011). However, fat-soluble vitamins such as provitamin A, vitamin D, and vitamin K are present in a very small amount in the pigmented rice varieties but are very feeble or not detected in the bread wheat varieties. For instance, black wheat contains 11.47 mg/ kg of vitamin K, seven times greater than conventional wheat. Vitamin K is impli­ cated in the blood-clotting process and bone metabolism (Suttie, 1992).

5.3.3 Betaine and Choline Whole wheat grain is the main source of betaine and choline. Several experimental studies show that whole-grain-based diets contain a sufficient amount of betaine and choline. Both betaine and choline play a defensive role against lifestyle-related dis­ eases. Choline is categorized as an essential nutrient and is synthesized via de novo synthesis pathways inside the cells. Choline is very important for living cells because its derivatives are mainly existing in the form of lipoprotein molecules, blood, and membranous lipids, and it acts as a precursor of the neurotransmitter acetylcholine. Choline and betaine are both providers of one carbon unit in the folate-dependent metabolism (Likes, Madl, Zeisel, and Craig, 2007). In the case of wheat grain, choline is distributed in different fractions, such as bran, germ, and flour. Currently, LC-dilution mass spectroscopy is used to estimate the amount of both choline and betaine in the different fractions of hard wheat (Triticum aestivum L. cv. Tiger) grown in the winter season. The amount of choline in aleurone, bran, and flour was 209 mg/100 g, 102 mg/100 g, and 28 mg/100 g, respectively. Individual concentrations of betaine are also quantified in aleurone, bran, and flour and consist of 1553 mg/100 g, 867 mg/100 g, and 23 mg/100 g of sample, respectively (Likes et al., 2007). Although the exact measurement of choline is difficult to make because it is present in the forms of glycerophosphocholine, phosphocholine, and phosphatidylcholine, which are major constituents of the plasma membrane in the cell.

5.3.4 Minerals Minerals are another class of micronutrients that are very essential for proper bio­ chemical and physiological functions in humans as well as animals. Wheat grain pro­ vides many minerals, which are required for nutritional purposes in the human diet. Most of the mineral content is present in the bran fraction of the wheat grain (Cilla et  al., 2019). Mineral content in the wheat crop is influenced by a wide range of environmental and genetic factors, as well as fertilizer and mineral content in the soil and their interaction. Moreover, the milling process substantially reduces the mineral content of wheat grains, which is reflected in white or refined wheat flour. The pearl­ ing process improves the mineral content because it releases the minerals entrapped in polysaccharides and components, such as hemicellulose, cellulose, lignin, and phy­ tate, in the cell wall.

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5.3.4.1 Phosphate (P) Several mineral ions are always bound with phytic acid, which constitutes the phy­ tate salts, for example, Fe, Ca, Mg, and Zn. In wheat grains, P is mainly present in the conjugated form of phytate, especially in the aleurone layer. Most of the phos­ phate content, up to 84%, is concentrated in the wheat bran. Phytate accounts for about 84% of the total phosphate present in the wheat bran. Moreover, phosphate is also associated with protein-rich globular structures, which are a type of granule. Thus, the bioavailability of phosphate from wheat-based food is poorly absorbed in the human digestive system. Experimental analysis shows that ancient wheat variet­ ies are rich sources of various minerals, except for phosphate (Igrejas, Ikeda, and Guzmán, 2020). The common wheat variety contains nearly 5.16 g/kg phosphate, while three ancient wheat varieties contain phosphate in the range of 3.71 to 4.74 g/ kg. Phosphorus deficiency substantially influences bone health in humans as well as animals. Recently, a low-phytate wheat mutant (lpa1–1) has been developed by using the mutagenesis method, which reduces the phytate content in the grain by up to 35%, so the bioaccessibility of inorganic phosphate in wheat grain is enhanced (Venegas, Guttieri, and Jr, 2022).

5.3.4.2 Iron (Fe) In wheat grains, Fe is mainly stored in the aleurone part, although its amount is higher in the crease region. Naturally, the crease region, which is surrounded by aleurone cells, offers minerals such as Cu, Fe, and Mn. The nucellar part abundantly contains Zn, K, and Ca. In the wheat grains, iron mainly occurs in the aleurone layer (bran) and often forms a complex with phytate in the form of myo-inositol phosphate 1, 2, 3, 4, 5, 6-hexa-kisphosphate that limits the bioavailability of iron in the diet of both humans and animals. Because mineral-phytate complexes are insoluble, they restrict the bioavailability of iron to humans and livestock. Currently, scientists are using many transgenic approaches to express indigenous phytase enzymes in the develop­ ing grain so that the mineral bioavailability can be increased (Brier et al., 2015). The interest in finding a heat-stable phytase enzyme is greater as it catalyzes the phytate complex hydrolysis at the time of food processing. Another alternative is to enhance the concentration of Fe in grains via crop-breeding programs. A comparison between common wheat and a few ancient grain varieties shows that the latter is richer and comprises iron up to 54.4 g/kg to 94.5 g/kg than common wheat, with 60.5 g/kg (Younas, Sadaqat, Kashif, Ahmed, and Farooq, 2020).

5.3.4.3 Potassium (K) The potassium ion is very important for facilitating many biochemical reactions and participates in numerous enzymatic reactions. Potassium is an integral part of the structural components of many biomolecules; hence it supports cell integrity. Moreover, potassium is also important for nerve impulse or nerve conduction, which is extremely important in multicellular organisms. The wheat grains tested for potas­ sium have been proved to be a good source of potassium with other elements too, which are essential for many biochemical reactions in human metabolism (Bahmanyar and Ranjbar, 2008). The common wheat (Triticum aestivum) consists of 4.74 g/kg of

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potassium, which is quite a lesser amount than ancient varieties (4.54 to 6.55 g/kg), and this amount is even greater than the RDA, that is, 4 g/kg (Zhang et al., 2010).

5.3.4.4 Zinc (Z) Zinc is another essential micronutrient for the growth of humans and animals. The deficiency of zinc can lead to the weakness of appetite, poor growth, delayed skin repair, and a weak immune system. So, an essential daily zinc amount must be supple­ mented to wheat-based foods. Although the concentration of Zn in wheat is relatively low, the aleurone and bran layers comprise zinc (Kaur et  al., 2021). Downstream processing of wheat is another important reason that can substantially reduce the amount of zinc in wheat-based flour, and, ultimately, the intake of zinc in the diet must be increased. Worldwide analysis of wheat grain composition indicates that the average Zn content is only 28.48 mg/kg. This amount is much less than the advised intake of zinc in the diet. The distribution of zinc varies in the three fractions, that is, bran, embryo, and endosperm, which are 14–16, 2–3, and 81–84% in the wheat grain, respectively. Some biochemical analysis also shows that the Zn content in bran is three times greater than that in the endosperm. Studies also show that the milling process reduces zinc content up to six times in refined flour (M. Wang, Kong, Liu, Fan, and Zhang, 2020). It is also observed that the Zn content of wheat grains also varies in the different genotypes grown in different locations in various countries.

5.3.4.5 Selenium (Se) To investigate the variation in the average amount of selenium among 150 bread wheat lines, different varieties of wheat for selenium content were analyzed; einkorn (278.9 µg/kg), emmer (229.2 µg/kg), and spelt (209.0 µg/kg). In wheat, the higher quanti­ ties of Se were in grains than in bread (80.8 µg/kg) (Zhao et al., 2009). Generally, selenium occurs in the form of selenomethionine (Se-Met) in wheat grains, which is mainly incorporated into proteins in the place of methionine. Selenium is also part of many crucial proteins involved in redox reactions, for example, selenoprotein occurs in the plasma membrane where it acts as a carrier of Se. Some enzymes that are involved in the neutralization of ROS, such as thioredoxin reductase, iodothyronine deiodinases, and glutathione peroxidases, mainly depend on the selenium ion for their catalytic functions. Being an essential trace element, the Se scarcity is responsible for many metabolic diseases (Mateo Anson et al., 2012). Selenium also protects against oxidative stress and cardiovascular ailments.

5.3.4.6 Manganese (Mn) Manganese (Mn) is another important trace element that contributes to the growth and development of humans. It supports many enzymes by acting as cofactors, which are very crucial in metabolic reactions. Like other nutritive components, Mn is present in a high quantity in the outermost layer of wheat grain, which means it is mostly present in the bran. Manganese deficiency influences mainly carbohydrate and lipid metabo­ lism and ultimately affects the growth and development and reproduction processes in animals and man (Xu et al., 2011b). Generally, the Mn concentration in wheat is in the range of 32.2–70.6 mg/kg in 250 Chinese genotypes of wheat. However, genotype

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and environmental interactions are a very crucial factor that decides the Mn content in wheat grain. Currently, experimental studies have proved that the use of high-level phosphate-based fertilizer in wheat crops grown on calcareous soil enhanced the Mn amount in the wheat grain (Barman et al., 2017).

5.3.4.7 Copper (Cu) Although copper deficiency does not occur in humans, its prolonged deficiency in the human diet can cause many adverse effects, for example, a low count of RBC and more frequent bacterial infections. Copper deficiency can be associated with defects in the connective, vascular tissue, and skeletal systems, and it helps to maintain strong bones and the immune system in humans. It also affects iron metabolism, which can lead to CVD and Alzheimer’s disease. The common wheat variety consists of a sub­ stantially higher concentration of copper (2.345 mg/kg), which is almost 53 times more than ancient species of wheat (Saini et al., 2021). Mineral deficiencies have very serious effects on health, productivity, and mental development that can last a lifetime. Moreover, the recommended amounts of miner­ als are not essential; rather, they must be available in a certain ratio in the human diet. Therefore, to fix these problems, the whole scientific community must work together.

5.4 Bioactive Phytochemicals Diets containing whole grains (WG), fruit, and vegetables are responsible for reducing the incidences of many noncommunicable diseases in humans, for example, obesity, metabolic syndrome, diabetes, cardiovascular disease (CVD), and cancer. A whole­ grain diet is proven to improve gut health and, simultaneously, reduce the risk of cancers, particularly colorectal cancer. The protective effects of whole grains can be attributed to the fact that whole grains contain a large number of bioactive compounds that positively impact overall metabolism and neutralize the effects of reactive oxygen species (ROS) or other harmful free radicals/ions. These ROS generally damage the genetic materials, proteins, and other vital biomolecules that are shielded by the bio­ active components of whole grains. Bioactive compounds act as antioxidants inside the cellular environment and hence retain the vitality of the living system. Therefore, whole-grain-containing diets are recommended by dieticians and different agencies all over the world. Because wheat grain and its various fractions (bran, aleurone, and endosperm) consist of bioactive and nutritive compounds, they are linked to good human health and a lower risk of chronic diseases (Angelino et al., 2017; Ktenioudaki, Alvarez-Jubete, and Gallagher, 2015). However, major sources of bioactive and nutri­ tive components are plants, animals, whole grains, fruit, vegetables, nuts, and oils. But there are certain groups of whole grains that are rich sources of bioactive agents. Bioactive and nutritive components are chemical agents or substances that mould biological or metabolic reactions inside a cell and living system. Initially, this defini­ tion was only applied to drugs that were used to treat illness in humans. But later on, based on antioxidants protective effects against the harmful effects of free radicals, changing energy, utilized, reducing inflammatory pathways, and control metabolic disorders, this definition is also applied to nondrug compounds. Due to their protec­ tive effects, phenolic compounds, flavonoids, carotenoids, vitamins, and minerals are

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now known as bioactive and nutritive components. But a pertinent question arises as to why plants have a very rich repertoire of phenolic-based bioactive compounds (Saini et al., 2021; Witkamp, 2022). Plants live in a sedentary mode of life to overcome negative effects induced by adverse environmental conditions in the surrounding ecosystem. Hence, plants have evolved various biochemical strategies by using bioactive components to neutralize the adverse effects of ROS, often produced by biotic and abiotic factors. In this section, the occur­ rence and distributions of bioactive and nutritive components present in the whole wheat grain and its fractions such as pericarp, germ, and endosperm will be discussed.

5.4.1 Phytochemicals Phytochemicals are synthesized in the primary or secondary metabolism of plants. Generally, phytochemicals are mainly involved in defense mechanisms to protect plants against microbes and insects (https://en.wikipedia.org/wiki/Phytochemical). Wheat grains consist of diverse types of phytochemicals, including phenolic com­ pounds, flavonoids, carotenoids, and other aromatic compounds. Currently, sophisti­ cated analytical techniques such as reversed-phase UHPLC/ESI-QTOF-MS are used to discover a wide variety of phytochemicals in wheat grain (Aloo, Ofosu, and Oh, 2021). In the case of whole wheat grain, an abundance of phytochemicals is mainly distributed in the bran and germ.

5.4.1.1 Phenolic Compounds Phenolic-based compounds are a very large group of aromatic compounds with a phenolic ring. Phenolic compounds act as bioactive compounds and are produced as metabolites in secondary metabolic pathways (e.g., the shikimic acid pathway, phen­ ylpropanoid pathway, and flavonoid pathway) with high levels of antioxidant, anti­ microbial, and anti-inflammatory activity that reduce the risk of noncommunicable lifestyle-related diseases and aging. Whole cereal grains are very rich sources of phe­ nolic compounds, particularly wheat-grain-based foods. The names of few important phenolic compounds and their distributions are given in the Table 5.3. In wheat grain, an abundance of the phenolic compounds is present in the outer layers of the grains. After the industrial revolution, the milling process was extensively used to produce refined flour or white flour from the endosperm part, containing starch and mostly lacking phenolic compounds and vitamins that are lost during the downstream pro­ cess of milling (Dhua et al., 2021; M. Sharma et al., 2016). Biochemically, phenolic compounds contain phenolic groups as a common struc­ tural feature. The biosynthesis of phenolic compounds is started by aromatic amino acids like phenylalanine and tryptophan. The deamination of phenylamine is cata­ lyzed by an enzyme called phenylalanine ammonia lyase (PAL), which is a regulatory enzyme of the aromatic acid biosynthesis pathway. Consequently, t-cinnamic acid is produced. This t-cinnamic acid is changed into p-coumaric acid by an important regulatory enzyme, cinnamate-4-hydroxylase (C4H). In the same metabolic pathway, many other phenolic compounds are produced, such as phenolic acids, coumarins, flavonoids, and lignans. Because phenolic compounds are a diverse group of aromatic compounds (Ma et al., 2022; H. Zhu, Liu, Yao, Wang, and Li, 2019), it becomes essen­ tial to first become familiar with the basic structure of phenolic structures and their

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FIGURE 5.2 Detailed classification of phytochemicals in the whole wheat grain. It shows different phenolics, carotenoids, flavonoids, and alkylresorcinols.

parent compounds and, simultaneously, with the most extended classification of phy­ tochemicals, including other phenolic compounds (see Figure 5.2). Phenolic acids are major building blocks for intricate cell wall matrices that exist in a variety of cereal grains, legumes, and other seeds. However, there are three main types of phenolic acids found in grains in free, conjugated, and bound forms. But the total phenolic compounds distributed in the wheat grains are divided into two major groups: (i) Hydroxybenzoic acids and (ii) hydroxycinnamic acids. The nomenclature is based on positions when any specific functional groups are attached to the C1–C6 and C3–C6 phenol rings. Phenols are linked with a carboxylic acid known as phenolic acid, and if a carboxylic acid as a functional group is linked to the phenol ring, then hydroxybenzoic acid is formed. This type of phenolic com­ pound is known as hydroxybenzoic acid. But when a phenol ring and a carboxylic acid functional group are separated via double carbon bonds (a C=C bond), then phenolic compounds are called hydroxycinnamic acids. There are a large number of derivatives of hydroxybenzoic acids, for example, p-hydroxybenzoic, vanillic, syringic, and gallic acids. Contrarily, derivatives of hydroxycinnamic acid are para­ coumaric, ferulic, caffeic, and synaptic acid (Tufarelli, Casalino, D’Alessandro, and

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FIGURE 5.3 Two major types of phenolic compounds, which are divided into various types of phenolic compounds present in the various parts of fractions of whole wheat grains.

Laudadio, 2017), and their classification is given in Figure 5.2. The chemical struc­ tures of both types of phenolic compounds present in the whole wheat grain are shown in Figure 5.3.

5.4.1.1.1 Ferulic Acid Among the phenolic acids, ferulic acid is more abundant than other acids like oxalic acid and p-coumaric acid, and it is present as esters and glycosides in whole wheat grain. Ferulic acid is always covalently conjugated to sugars, polysaccharides, glycoproteins, polyamines, and lignin in the plant cell wall. Ferulic acid is mainly distributed in the different parts of the whole grain and, more specifically, the embryo and pericarp, but a meager amount is also stored in the starch-rich endosperm (see Table 5.3). However, the wheat bran is considered a rich source of ferulic acid, where it is linked to hemicellulose, a cell wall polysaccharide, via ester bonds in cell walls (Dhua et al., 2021). Wheat grains contain about 0.8–2 g of ferulic acid per kg of dry wt., which accounts for 90% of all phenolic compounds. It is already noted that cereals contain ferulic acid in three different forms: free, soluble, and conjugated. Insoluble or bound forms of ferulic acid make up roughly 90–95% of the total amount (Lu et al., 2014), so it is concluded that wheat comprises a much higher amount of bound ferulic acid than the free forms. In comparison to the hard wheat variety, soft varieties appear to have a larger concentration of ferulic acid. In plant cell walls, ferulic acid and other phenolic acids produce a sort of chemical and physical barrier by cross-linking saccharides/ glycans that act against microbial infections and free radical damage. Ferulic acid also possesses astringent properties that keep animals and insects away from plants and seeds. Ferulic acid is a strong antioxidant like other phenolic compounds. Its mode of

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action is mediated by donating one hydrogen atom from its phenolic hydroxyl group in response to free radicals (Kumar and Pruthi, 2014). The two most potent effects of ferulic acid on human health are free radical scavenging and anti-inflammation, and both have been proven by many scientific investigations. Ferulic acid has been proven to be very effective in treating noninfectious diseases such as Alzheimer’s disease, heart diseases, type-2-diabetes, cancers, and skin diseases. But there are certain chal­ lenges – for example, its proper inclusion in the diet and the quantification of the exact amount for a daily recommendation.

5.4.1.1.2 Sinapic Acid Sinapic acid is the main hydroxycinnamic acid that has a very predominant presence in the plant kingdom, including fruits and vegetables, whole cereal grains, oil-con­ taining seeds, spices, and medicinal plants, and, thus, it is a very common pheno­ lic acid in the human diet. Generally, sinapic acid is always found in the form of esters of sugar (glycosides) and organic compounds, for example, sinapoyl esters and sinapoyl malate (Saini et al., 2021). After ferulic acid, sinapic is the most impor­ tant phenolic acid present in wheat, which accounts for 10 to 12% of total phenolic compounds (see Table 5.3). Canadian wheat varieties comprise up to 17 to 31 μg/g of sinapic acid in the wheat flour, but vegetables from the Brassicaceae family contain a very high amount – nearly 100 μg/g. Sinapic acid and its derivatives belong to the Brassicaceae family (Tian, Chen, Tilley, and Li, 2021). It shows a high level of antioxidant activity against oxidative stress and antimicrobial, anti-inflammatory, anticancer, and anti-anxiety activity. There are two main sinapic-acid-based deriva­ tives, such as 4-vinylsyringol and sinapine or sinapoyl choline, which are respon­ sible for overcoming the aforementioned health problems in humans hence, currently being added to food processing, beverages, health products, and pharmaceuticals (Nićiforović and Abramovič, 2014).

5.4.1.1.3 P-Coumaric Acid p-Coumaric acid is a hydroxyl-group-containing cinnamic acid. It is exists in low quantity at the center of the grain and has a higher amount in the outer layers of whole wheat grain. This phenolic acid is of high significance due to its chemoprotective and antioxidant properties. Most recently, the amounts of various phenolic compounds have been estimated by using the LC-ESI-MS/MS analysis. p-Coumaric acid up to 1.360 µg/g DW was present in the highest amounts in the grain and grass of traditional and modern wheat varieties (Aslam et al., 2021).

5.4.1.1.4 Caffeic Acid Caffeic acid has a great potential to scavenge harmful reactive oxygen species (ROS). Caffeic acid is a naturally occurring cinnamic acid that is largely involved in lignin production. In several studies, caffeine has been linked to the regulation of cell devel­ opment, turgor balance, photoperiodism, and plant–water relationships. Caffeic acid and its derivatives have a higher antioxidant capacity to protect plants from biotic and abiotic stresses – for example, the adverse effects of high temperature, water scarcity, heavy metal ions, and saline stress by regrowing roots and by upregulating antioxidant enzymes that modify the transcription of salt-tolerant genes. It also improves plant and water interactions and effectively scavenges ROS in plants. But the mechanism

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responsible for inferred tolerance against many forms of adverse environmental con­ ditions is still poorly understood (Ma et al., 2021). Phenolic acids are quantified in the two wheat varieties. The results show that feru­ lic acid has a high concentration, followed by other phenolic acids such as sinapic, syringic, vanillic, and p-coumaric acids see Table 5.3. Although the concentration of these phenolic compounds is very much influenced by the environmental conditions, the content of ferulic and sinapic acids was higher in the winter variety than that in the spring variety (Ahmad and Al-Shabib, 2020). The concentrations of caffeic acid, ferulic acid, p-coumaric acid, syringic acid, vanillic acid, and sinapic acid were 107, 268, 18.5, 24.4, 29.1, and 121 µg/g, respectively. Moreover, it was also observed that ferulic acid accounts for 48% and 60% of the bran of two spring and winter wheat grains, respectively (Katileviciute et al., 2019).

5.4.2 Carotenoid Carotenoids are a major group of lipophilic bioactive compounds with many conju­ gated double bonds known as carotenoids. The number of carotenoids determines the pigment colors, which are responsible for the color of wheat grain. The major source of carotenoids is bran because of its excessive presence in the outer seed coat. Foods prepared from whole wheat grain have a bright yellow color due to the presence of carotenoid pigment, which is also an important parameter for food quality. The aver­ age carotenoid value is about 6.2 mg per kg of dry weight in the case (Borel and Desmarchelier, 2018; Mateo Anson et al., 2012) of durum wheat. Chemically, carotenoids are 40 carbon-containing tetraterpenoid compounds containing a very reactive system of conjugated double bonds. This conjugation of double bonds makes carotenoids very interactive with ROS, and, thus, carotenoids are responsible for color and antioxidant activities. Carotenoids are synthesized from the very basic compound isoprenoids, which have a specific linear and sym­ metric arrangement of eight isoprenes. The basic cyclic structure of carotenoids can undergo many chemical changes, for example, dehydrogenation, hydrogenation, cyclization, and oxidation reactions. Therefore, it efficiently neutralizes the harm­ ful RNS and ROS synthesized in response to biotic and abiotic stress inside the living systems (Ficco et al., 2014). In wheat grain, carotenoids are estimated, such as lutein, β-carotene, zeaxanthin, β-cryptoxanthin, β-apocarotenal, and antheraxan­ thin (see Figure 5.4). Food-processing methods, both milling and cooking, substan­ tially damage the carotenoid pigments, but, still, some pigments are stable even at a higher temperature. During the storage of wheat grains and flour, carotenoids are reduced due to enzymatic and nonenzymatic oxidation reactions. Due to the bond conjugation process, double bonds absorb light. Hence, both temperature and light affect the biochemical activity of various types of carotenoids (Abdel-Aal, Young, and Rabalski, 2007).

5.4.2.1 Lutein Among the major carotenoids, lutein is very significant, and it accounts for 70–80% of the total carotenoids present in the wheat grain, while the rest are zeaxanthin and β-carotene. For example, einkorn, Khorasan, and durum wheat varieties and

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FIGURE 5.4 Structure of various types of carotenoids occurring in the whole wheat grain and its various fractions.

corn are rich sources of lutein and zeaxanthin. Bread made from modern wheat varieties contains small amounts of lutein and zeaxanthin, whereas bread made from ancient wheat varieties comprises large amounts (Melini, Melini, Luziatelli, and Ruzzi, 2020). The highest value of zeaxanthin was noticed in einkorn wheat, followed by the other four durum, emmer, spelt, and bread wheat. Ancient wheat varieties are also rich sources of carotenoids. Einkorn (T. monococcum), ancient diploid wheat, provides lutein up to 8.41 mg/kg on a dry weight basis. The amount of lutein in various fractions of wheat grain, especially the aleurone layer, starchy endosperm, and germ, comprises about 0.425, 0.557, and 2.157 mg per kg, respec­ tively (Oduro-Obeng, Apea-Bah, Wang, Fu, and Beta, 2022). Many experiments show that high amounts of lutein in wheat flour induce the yellowish color of wheatflour-based noodles.

5.4.2.2 Zeaxanthin Zeaxanthin is a great ROS quencher and protects against the harmful effects of oxida­ tive stress, hence it is categorized under potential bioactive compounds. Other benefits of zeaxanthin are also documented, such as the reduction of age-related ailments, antiretroviral, malignant tissue, and ocular disorders. Therefore, the supplementa­ tion of lutein and zeaxanthin into foods, drugs, nutraceuticals, and cosmetics is gain­ ing ground at the current time. The einkorn and durum wheat varieties contain high amounts of carotenoids, but zeaxanthin is dominant, followed by α and β-carotene, β-cryptoxanthin, and lutein (Garcia Molina et al., 2021; Paznocht, Kotíková, Orsák, Lachman, and Martinek, 2019). Biochemically, zeaxanthin can change into moon­ epoxidized xanthophyll antheraxanthin and another xanthophyll-based violaxanthin, but it could not be estimated in wheat grain. Different parts of wheat grains contain various amounts of zeaxanthin, for instance, the fractions, that is, endosperm, aleu­ rone layer, and germ contain 0.557, 0.425, and 2.157 mg/kg of grain, respectively. In other experiments, zeaxanthin was estimated in aleurone and germ fractions with its

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amounts recorded as 0.776 and 3.094 mg/kg, but it is lacking in the endosperm com­ pletely (Lachman, Martinek, Kotíková, Orsák, and Šulc, 2017). Moreover, colored wheat varieties, for example, purple wheat, consist of a higher quantity of lutein, particularly in the aleurone part (0.534 mg/kg) and lowest in the germinal part (1.714 mg/kg). The content of carotenoids is more in colored wheat cultivars as compared to noncolored wheat varieties. These results can be ascribed to color, which indicates high amounts of carotenoids, especially in the colored wheat variety (Lachman et al., 2017).

5.4.2.3 β-Cryptoxanthin β-Cryptoxanthin is the most important oxygenated carotenoid and bioactive agent containing provitamin A  activity. It is mainly present in fresh fruits, vegetables, and whole grains. The high concentration of β-cryptoxanthin in the serum is linked with a lower mortality rate in humans and is a great protectant against free radicals. β-Cryptoxanthin is utilized as a food supplement and additive and is also used as a natural food colorant. Biochemical analysis of 11 wheat varieties shows differences in the quantities of lutein, zeaxanthin, and β-cryptoxanthin by 5-, 3-, and 12-fold, respectively (Titcomb et al., 2018). The β-cryptoxanthin amount in wheat varieties ranged from 1.12 (0.13 g of β-cryptoxanthin/100 g of grain for W7985) to 13.28 (0.430 µg of β-cryptoxanthin/100 g of grain for Stoa variety with a 12-fold differ­ ence (p < 0.01)). Free β-cryptoxanthin and β-cryptoxanthin esters are distributed in the grain (Titcomb et  al., 2018), but their distribution depends upon the cultivars, environmental conditions, growing sessions, extraction techniques used, and storage temperature of grains.

5.4.3 Flavonoids Flavonoids are another major group of phenolic compounds that occur in wheat grains. Currently, about 5,000 types of flavonoids and related compounds have been identified and stored in databases. There are major flavonoids occurring in the whole wheat grain, and its various fractions are shown in Figure  5.5. Chemically, flavo­ noids contain a 15-carbon skeleton or parent compound consisting of two phenyl rings (referred to as “A and B rings”) and a heterocyclic ring (the C ring), which is given in Figure 5.5. Flavonoids are divided into six different classes on the basis of their molecular structure, namely anthocyanidins, flavan-3-ols, flavanols, flavanones, flavones, and isoflavones, which are part of human diet. Flavonoids occur in the form of C-glycoside, and various types of flavone-C-glycosyl derivatives are present in the whole grain and its different fractions, such as germ, endosperm, and bran, so that this flavone-C-glycoside can act as biomarkers to identify the products produced from whole-wheat flour or refined flour (Dhua et  al., 2021). These flavonoids are also responsible for the yellow pigment, which gives a specific color to wheat grain because anthocyanins are mainly present in the outer layers. It is well known that wheat grains are also colorful or pigmented – for example, black-grained wheat cul­ tivars comprise a high content of anthocyanins, like blue- and purple-colored wheat grain with a purple pericarp. Whole wheat grains with yellow pigments comprise mainly four groups of flavonoids – for example, flavones, flavonols, flavanones, and flavans (Singla et al., 2019).

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FIGURE 5.5 There are many types of flavonoids, such as anthocyanidins, flavan-3-ols, flavonols, flavanones, flavones, and isoflavones, which are mainly present in wheat grain. Nowadays, flavonoids are also included in the human diet because of their health benefits.

5.4.3.1 Flavan-3-ols Generally, three polyphenols-based compounds, flavan-3-ols, flavan-4-ols, and flavan­ 3,4-diols, are synthesized in a flavonoid metabolic pathway. Flavan-3-ols with proan­ thocyanidins are responsible for giving rise to brown-color compounds by oxidation reaction. Some wheat varieties, particularly red-grained wheat coats, contain reddish brown-colored hydrophobic phlobaphenes (deoxy flavonoids) produced by oxidation and polymerization reactions (Leváková and Lacko-Bartošová, 2017).

5.4.3.2 Flavonols One of the major flavonols is the apigenin C-glycosides that are mainly present in the durum and bread wheat varieties. For example, tricin, the most important flavonoid, is often used as a nutraceutical and is mainly present in the pericarp and aleurone layers of wheat grain (Lachman et al., 2017). Recently, different 32 flavones have been iden­ tified in wheat grain samples by using the UPLC-QTOF-MS which mainly includes 21 C-glycosidic forms, 7 O-glycosidic forms, and 4 aglycone compounds (LiyanaPathirana and Shahidi, 2006). Several experiments show that red wheat contains a higher content of flavonoids, particularly flavonols, than white wheat. For example, it contains flavones in the range of 41.2 to 1126.0 µg/kg mg/kg flavones (apigenin, luteolin) (Lachman et al., 2017).

5.4.3.3 Flavanones The bran fraction of wheat grain comprises flavanones, for example, naringenin. Additionally, wheat bran also contains minute amounts of catechin and its di-, tri-,

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and oligomeric proanthocyanidins. Two major techniques, such as multistage highresolution mass spectroscopy and mass defect filtering, are used to extract flava­ nones from wheat germ (Anunciação et  al., 2017). Flavanones are also used as biomarkers, which are generally used to discriminate between whole grains and refined wheat flour.

5.4.3.4 Flavones Flavones are very important flavonoids in plants, which mainly act as natural pesti­ cides against insects and fungi. Blue-colored flavones protect plants from UV-based damage because they consist of a double bond between C2 and C3 in the flavonoid skeleton. However, there is no functional group with C3 position. The main flavone, apigenin C-glycosides, is mainly present in the wheat variety of Triticum durum (Geng et al., 2016).

5.4.3.5 Isoflavones Isoflavones participate in many antimicrobial mechanisms against many types of fun­ gal pathogens. Isoflavonoid phytoalexins isoflavones are polyphenols mainly avail­ able in legumes, fruit and vegetables, and nuts. Although soybeans and soya-based foods are the main sources of isoflavones which are conjugated with glycosides, for example, daidzin, genistein, biochanin A, and formononetin. Generally, isoflavones are hardly detectable but if supplemented exogenously for example, soybeans and tofu-based okara that substantially enhanced the nutrition value of wheat-based food (Rinaldi et al., 2000).

5.4.3.6 Anthocyanin Anthocyanins are major water-soluble aromatic compounds that act as natural pig­ ments and mainly impart colors to grains, fruits, and vegetables. Anthocyanins are flavonoids represented by the aglycones and their glycosylated and acylated forms. Aglycone is a parent compound of anthocyanins that are attached to various types of sugars via hydroxyl groups at different positions. Individual anthocyanins differ from each other in respect of the number of hydroxy- or methoxy-groups of aglycones and particularly linked sugars by using O-glycosidic linkage at various positions (Figure  5.6). Furthermore, aliphatic or aromatic acids are linked with these sugars (He and Giusti, 2010).

5.4.3.7 Proanthocyanidin Proanthocyanidin is a major class of flavonoids that are oligomers of catechin and epicatechin and esters of gallic acid. Phlobaphenes are mainly tannins, which are associated flavonoids synthesized by the nonenzymatic oxidation reactions of color­ less polymers. The content and composition of various anthocyanins like delphinidin­ 3-glucoside, delphinidin-3-rutinoside, and malvidin-3-glucoside are varied in various colored wheat varieties. Ancient wheat varieties are a very rich source of proanthocy­ anidins, especially in bran (Ma et al., 2021). Wheat bran contains a very small amount

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FIGURE 5.6 Structure of anthocyanins present in wheat grains.

of catechin procyanidin units. Although dimeric proanthocyanidins also include di-, tri-, and oligomeric proanthocyanidins, their detection is interfered with by methoxy hydroquinone glycosides (Dinelli et  al., 2011). Hence, the detection of these com­ pounds is very complicated. The composition of anthocyanins is mainly determined by environmental and genetic factors, such as the combination of genes and shade, which gives rise to a very dark or black color for grains. Several factors, such as the spike, shading, mag­ nesium-based fertilizers, and harvesting time of wheat crops, are also responsible for the amount of anthocyanin in plants (Matus-Cádiz et  al., 2008). Recently, genetic and breeding programs have been launched to enhance the anthocyanin content in wheat varieties.

5.5 Benzoxazinoids (BXs) Benzoxazinoids are other important phytochemicals present in whole wheat grain and rye, but the bran fraction is the major site where they are present in abundance. Currently, very sophisticated techniques like UPLC-qTOF-MS and LCMS are used to identify a range of benzoxazinoid metabolites, especially the hydroxamic acids (2,4-dihydroxy­ 1,4-benzoxazin-3-one based compounds such as DIBOA; 2,4-dihydroxy-7-methoxy­ 1,4-benzoxazin-3-one, DIMBOA); lactams (2-hydroxy-1,4-benzoxazin-3-one, HBOA); and benzoxazolinone (1,3-benzoxazol-2-one, BOA) (Shavit, Batyrshina, Dotan, and Tzin, 2018). Initially, the benzoxazinoid metabolites were found to be very effective against plant pathogens and acted as allelochemicals. The allelochemicals are natu­ ral products that help in communication among plants, with other plants, insects, or microbes, and are very important in plant microbes interactions. Several investiga­ tions have proved that benzoxazinoids are effective in anti-cancer, anti-allergy, and anti-inflammation. More recently, they found them to be quite effective against several cancerous cell lines – for example, the prostate cancer cell line. Furthermore, the most abundant water-soluble compound, 2,4-dihydroxy-1,4-benzoxazin-3-one (DIBOA),

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Nutritional Composition of Wheat Grains TABLE 5.3 The Amount of Phenolic Acid in Various Fractions of Wheat Grain (μg/g) Phenolic Compounds

Whole Grain

Wheat Bran

Wheat Aleurone

Ferulic acid Ferulic acid dimers Sinapic acid p-Coumaric acid Syringic acid Vanillic acid

399–870 19–150 13–18 15–28 13–18 4.9–21

4,610–5,670 780–1,550 115–276 130–162 57.2 16.5

6,440–7,980 360–950 269–353 160–288 90.3 20.0

Source: Data from Barron et al. (2007); Hemery et al. (2009, 2010, 2011); Li et al. (2008); Noort et al. (2010); and Zhou et al. (2004)

caused the cell death of prostate cancer cells and ultimately reduced the growth of cancer tumors (Hanhineva et  al., 2011; Landberg et  al., 2019). The information related to their bioavailability, stability, absorbability, chemical modifications such as glucurono and sulfoconjugation, and the influence of gut microbial processing of benzoxazinoid metabolites is still not known.

5.6 Lignans It is already mentioned before that lignin is the polymer of p-coumaryl, coniferyl, and sinapyl alcohols, which get polymerized through enzyme-based processes. Both lignans and lignin phenolic-based compounds occur in the bran part of wheat grain, which accounts for 3 to 7% of total dietary fiber. Owing to their polyphenolic struc­ ture, lignin and lignans are responsible for a high level of antioxidant activity, for example, protecting DNA against oxidative damage in cells (Eriksen et  al., 2020). Lignin is the most important component of insoluble dietary fiber, which turns into the lignans and has been proven effective against colon cancer because of its effective­ ness in disposing of excretory materials from the gut. Plant lignans belong to the phytosterols, which are chemically plant-based dipheno­ lic compounds. They resemble the 17-estradiol types of hormones. Plant lignans are responsible for reduced incidence of chronic diseases if included in human diets. The high concentrations of up to 6,700 μg/g and 2,270 μg/g of lignans are noticed in rye and wheat, respectively (Eriksen et al., 2020).

5.7 Alkylresorcinols Alkylresorcinols are another class of phenolic compounds that occur in the exter­ nal layer of whole wheat grains. They are also known as resorcinol lipids and are made up of resorcinol-type phenolic rings with odd-numbered aliphatic chains. The saturated aliphatic side chain in wheat-based ARs often contains 17, 19, 21, 23, or 25 carbons (Figure 5.7). Additionally, ARs also have unsaturated side chains, which have also been discovered in many other kinds of cereal (Mateo Anson et al., 2012). Alkylresorcinols are sort of biomarkers to identify whole-grain-based food products.

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FIGURE 5.7 Alkylresorcinols, lignans, and benzoxazinoids are very significant bioactive com­ pounds that are currently used as biomarkers and nutraceuticals. Phytosterol is another significant compound that shows a great resemblance to cholesterol, behaves like the hormones in the plant, and has several biological properties that protect against cardiovascular diseases.

Because alkylresorcinols (ARs) are present in abundance in the outermost layer of grains, they are also found in whole-grain barley, wheat, and rye. So far, 100 differ­ ent types of ARs have been identified in plants and microbes (Landberg et al., 2019). To track the consumption of whole-grain products in the diet, ARs and their deriva­ tives act as very promising biomarkers (McKeown et  al., 2016). ARs are extracted in organic solvents – for example, acetone, ethyl acetate, and alcohol. The amount of ARs in various 175 genotypes of wheat ranged between 191 and 741 μg per gram of flour. Given the current scenario, future research related to ARs must be focused on how many food-making processes such as baking affect AR content, particularly those with unsaturated side chains. The concentration of ARs also depends upon genetics and environmental conditions. Therefore, creating new wheat genotypes with increased total AR content is an interesting new area of food research.

5.8 Phytosterol Structurally, phytosterol shows a great resemblance to cholesterol, which is 27 carbon compounds associated with cardiovascular diseases although phytosterols contain an additional methyl or ethyl group linked to the sterol ring (Yoshida and Niki, 2003). In the case of wheat, almost 50% of all sterols come from phytosterols and sitos­ terol, but other sterols like campesterol, sitostanol, and campestanol are also present. GC-MS analysis (Prinsen, Gutierrez, Faulds, and Del Rio, 2014) clearly shows that phytosterols are present in either free or bound form with glycoside and ester con­ jugates. Biochemical analysis of 175 different wheat genotypes revealed total phy­ tosterol concentrations in whole-wheat flour ranging from 670 to 1,187 μg/g. Total phytosterol content is comparable to phenolic acid concentration, which is commonly

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accepted as the main phytochemical in whole wheat grains. Phytosterols have a reduc­ ing effect on cholesterol and cancerous growth (Ramprasath and Awad, 2015; Tian et al., 2022). However, compared to phenolic acids, their general health advantages have received very little attention.

5.9 The Significance of Bioactive Compounds in Human Health 5.9.1 Obesity and Weight Management In the above discussion, it is mentioned that wheat grains have numerous bioactive complexes which are responsible for reducing the possibility of the onset of obesity. Certain noncommunicable diseases such as metabolic syndrome, insulin resistance, diabetes mellitus, high blood pressure, CVDs, lack of sleep, and cancers are associ­ ated with excess body weight or obesity. Generally, triacylglycerols (TAGs) are long­ term fuel in the human body, which provides more energy than carbohydrates and protein after their complete oxidation in the cell. But the excessive deposition of TAGs in the tissues under the subcutaneous layer of skin is harmful, which is also known as obesity or being overweight (Chooi, Ding, and Magkos, 2019; Kopelman, 2000). Many international agencies have tried to present a unitary definition of obesity based on bodily symptoms. According to the National Institutes of Health (NIH) and the World Health Organization (WHO), obesity can be defined as having a body mass index (BMI) of over 25, and a man having it is considered overweight, and if with BMI over 30, he is being considered obese [www.who.int/westernpacific/health-topics/obesity]. Currently, obesity is one of the most serious public health challenges of this century, which is present in most countries worldwide. Earlier, obesity was more prevalent in developed countries after the great industrial revolution, but now it equally affects all countries. The occurrence of obesity has increased threefold in the last four decades, considerably spoiling public health (Ogden, Yanovski, Carroll, and Flegal, 2007). Extreme obesity can be attributed to the eating of refined flour in the form of fast foods, which certainly lack bioactive and traditional nutritive compounds that are generally present in whole grains. Many short- [3 years] and long-term [12 years] experimental studies indicate that the consumption of a wheat-grain-based diet is inversely proportional to the incidence of obesity and being overweight. In similar studies, characteristics such as weight change, waist perimeter, body adiposity index, and consumption of dietary phyto­ chemical index were measured for 3  years, reflecting the less frequent occurrence of obesity in adults who consumed whole grains (Liu et al., 2020; Witkamp, 2022). Several experimental proofs are put forward in support of the consumption of whole wheat grain-based diets, which create certain physiological effects that help in body weight management. Whole wheat grain is provider of traditional nutritive agents such as vitamins and their coenzymatic forms that enhance carbohydrate and lipid metabolic rates. Moreover, wheat grain diets provide more dietary fiber, nutrients, and phytochemicals with lower energy density; increase satiety; improve the glyce­ mic response; and reduce insulin resistance. Furthermore, it was also observed that wheat consumption also reduces concentrations of biochemical factors such as insu­ lin, C-peptide, and leptin.

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In a highly significant study, whole-wheat bread was fed to two groups of 50 Japanese human subjects with BMI more than 23 kg/m2. One group fed on 100 g of refined flour while the other group fed on whole-wheat bread and refined wheat bread for 12 weeks (Liu et al., 2020). After that, it was observed that whole-grain consump­ tion promotes less weight gain, particularly visceral fat. Experimental studies also show that a whole-grain diet also improves several signal molecules such as adiponec­ tin, which are produced in the adipose tissues and lead to weight loss and have a posi­ tive effect on both fat and carbohydrate metabolism, energy balance, and biomolecule homeostasis, which consequently reduces the deposition of fat in the body. Whole-grain diets have a low glycemic index, which is further characterized by high satiety and low digestion and absorption that can be attributed to dietary fiber. Dietary fiber mainly binds with water and makes a thick cluster-type structure that delays the absorption of glucose, thereby reducing the requirement for insulin and maintaining glucose homeostasis. It is also observed that two main digestive hor­ mones secreted from the small intestine help in the maintenance of postprandial glu­ cose and, ultimately, glucose and fat metabolism (Witkamp, 2022). Recently, many studies have linked gut microbiota and obesity, which shows that whole cereal grain consumption positively promotes the good gut microflora composi­ tion that feeds on short-chain fatty acids (SCFAs) and hormones that regulate appetite management, given that the wheat bran is provider of dietary fibers (DFs) and its consumption modulates gut microbiota. Moreover, microflora produces specific types of metabolites that promote the growth of mucus-producing microbes to improve the intestinal barrier, which is very important for the regulation of body weight and com­ position by acting as metabolism-based energy sources. A few experiments show that the whole grain contains prebiotics that positively affect the growth of gut bacteria that lower fat accumulation through the production of a variety of lower molecular weight unique metabolites (Esposito et al., 2005; Khan et al., 2022). Additionally, SCFAs play very important roles in the regulation of liver and blood glucose and lipid catabolism and thus promote the secretion of two of the most important gut hormones, peptide-YY and glucagon-like peptide 1 (GLP-1), hence they regulate fat synthesis in the body (Mansour, Hosseini, Larijani, Pajouhi, and Mohajeri-Tehrani, 2013). The consumption of wheat bran dietary-based fiber pro­ motes the growth of Akkermansia muciniphila in the gut of rats. One of the most common gut bacteria, for example, Prevotella, is linked with the improvement of glucose metabolism, which depends upon the amount and type of dietary fiber. The ratio of the two most important gut strains, Prevotella and Bacteroides, increases on the dietary fiber of the wheat bran via fermentation inside the gut (Prasoodanan P K et  al., 2021). Moreover, Prevotella and Bacteroides secrete antibacterial agents that reduce harmful bacterial growth and also prove helpful in the reduction of body fat attributed to low appetite or satiety, slow gastrointestinal transit, and a change in glucose metabolism.

5.9.2 Metabolic Syndrome Metabolic syndrome is a major medical problem in middle-aged people and affects almost 25% of the population worldwide, especially in developed countries. Metabolic syndrome is a prior medical condition characterized by glucose intolerance, pre-dia­ betic, hypertension, CVD, fatty liver, excessive central belly fat, insulin resistance, and

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hyperlipidemia. Additionally, metabolic syndrome is also linked with inflammation, hyper-cholesterolemia, nonalcoholic fatty liver, gallstone disease, and impotency in men (Samson and Garber, 2014). These conditions can lead to many lifestyle-related problems such as heart disease, T2D, and stroke, which are responsible for most deaths in middle age. Metabolic syndrome is characterized by high plasma triacylglycerol (TAG) (≥150 mg/dL), fasting glucose (≥100 mg/dL), low level of high-density lipopro­ teins (HDL) (88 cm for women) (Eckel, Grundy, and Zimmet, 2005). To overcome the problem of metabolic syndrome, several mea­ sures are recommended, which include drugs, lifestyle changes, and a plant-based diet, particularly the dietary fiber-rich diet provided by whole cereals. Plant-based diets have proved to be highly effective against metabolic diseases. In 13-week long experi­ mental study carried out on 29 individuals, the results showed a lower body weight and improved levels of HDL cholesterol, thus once again underlining the significance of a whole-grain-rich diet (McGrath and Fernandez, 2022). Given the above discussion, whole wheat grain comprises many bioactive compo­ nents as mentioned in the table which is proven effective in various human diseases related to lifestyle, but they are equally effective in treating metabolic syndrome. In a total of 14 studies on humans, it showed that eating a whole-grain-based diet was inversely linked with a less number of metabolic syndromes, while refined grain eating is positively linked with metabolic syndrome. In a significant study carried out on the Taiwan population, three types of diets were supplied to 26,016 people (Guo, Ding, Liang, and Zhang, 2021). These diets contained meat-rich and rapid food dietary systems, vegetable-based seafood dietary patterns, and cereal and dairy dietary patterns. Among them, the cereal–dairy dietary pattern involved six food items such as flour products, whole-grain diets (including whole-wheat bread, brown rice, mixed cereal grains, and oat-based meal), root crops, and dairy products. Their consumption decreases the occurrence of metabolic syndrome in the subjects. This can be linked to the cereal dairy dietary pattern, which comprises complex glucans, dietary fiber, phytochemicals, antioxidants, prebiotics, and probiotics (Giacco et al., 2014; Syauqy, Hsu, Rau, and Chao, 2018). Although similar types of studies are also conducted on the Iranian and French populations, metabolic syndrome affects them irrespective of all geographic loca­ tions, food types, and food habits. In both studies, fiber-rich diets were accountable for the lower incidence of metabolic syndrome. The presence of 3-(3,5-dihydroxyphenyl)­ 1-propanoic acid (DHPPA) in blood plasma, a well-recognized biomarker that reflects the consumption of a whole-grain wheat diet. Higher DHPPA amounts in the plasma are negatively related to metabolic syndrome when compared to subjects with lower DHPPA amounts in their blood plasma. Authors have ascribed these findings to whole-grain consumption because whole grains offer vitamins, minerals, dietary fiber, phytochemicals, and antioxidants that protect against metabolic syndrome (L. Zhou et al., 2022). Moreover, alkylresorcinols include a large number of phenolic lipid compounds present in the bran fraction of wheat grains. However, alkylresorcin­ ols contain fewer hydrogen donation and peroxyl-scavenging capabilities, but they are still effective against lipid peroxidation in plasma membranes due to the long alkyl chain in alkylresorcinols (L. Zhou et al., 2022). Inflammation is another sign or symptom that appears in metabolic syndromes, including CVD and insulin resistance. Inflammation is also responsible for creating

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prediabetes and cardiovascular diseases. But bioactive components and nutritive com­ pounds available in the wheat grain, particularly in the bran, the outer layers, play a very important role in reducing inflammation and offering antioxidant power.

5.9.3 Cardiovascular Diseases (CVD) CVD is a group of diseases that mainly include coronary artery diseases (CAD), for example, angina, heart attack, stroke, weak heart, cardiomyopathy, genetic heart dis­ ease, and valvular heart disease. Higher consumption of whole wheat grains and their derived products was associated with a reduced risk of CVD. The incidence of CVD can be reduced by almost 20 to 30% by the eating a whole-grain diet (Chapagai and Fink, 2022).

5.9.3.1 Hypertension Hypertension is a medical condition that is mainly responsible for the damage of vital body organs for example, the heart, brain, and kidneys and is a major reason of prema­ ture deaths worldwide. According to an estimate, 1.28 billion people aged between 30 and 79 years will have hypertension in developing countries. Notably, 46% of affected people do not know they are suffering from high blood pressure, so it is also known as “a silent killer”. According to WHO, “hypertension is diagnosed if, when it is mea­ sured on two different occasions, the systolic blood pressure readings on both days is ≥140 mmHg and/or the diastolic blood pressure readings on both days is ≥90 mmHg” (www.who.int/news-room/fact-sheets/detail/hypertension). A few epidemiological and human-based studies in the United States were con­ ducted on 29,000 women who consumed a minimum of four servings of whole grains. Parallelly studies were also carried out on women who were eating a 23% wholegrain-based diet (Poutanen et  al., 2022). The experimental data show that the first group was less prone to hypertension. In an important study with 88 subjects, wholegrain-based diet was tested, whereby twice as many subjects eating whole oat cereal promoted good health and reduced their hypertension medication when compared with the control group that did not consume whole oats. In a nutritional approach called the Dietary Approaches to Stop Hypertension (DASH) trial, whole grains were included in the various dietary formulations to lower blood pressure (Jones and Engleson, 2010). In the case of hypertension, many experiments were carried out to assess the effects of a whole-grain-based diet on hypertension in comparison to other chronic diseases. But both intervention and epidemiological studies indicate the same type of results for whole-grain consumption. But still, there are many unresolved issues related to whole wheat grain consumption and the effectiveness of the holistic effect of all the bioactive and nutritive components present in the whole grain against diseases. Furthermore, a pertinent question arises about how much contribution of individual components for instance, dietary fiber, phenolic compounds, vitamins, and mineral is needed to resist the CVD. Many researchers concluded that a higher intake of whole grains pro­ motes a lower reading of blood pressure, which can be attributed to the fact that whole grains contain a higher level of dietary fiber, which is responsible for lowering hyper­ tension (Saleh, Wang, Wang, Yang, and Xiao, 2019) although a few investigations are carried out on individual components of wheat grain, such as phytosterols and

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alkylresorcinols, as a dietary formulation. There is also a need to study the combined effects of whole grains and lifestyle-related changes on CVDs. The exact biochemi­ cal mechanisms that are responsible for the relationship between WGs and hyperten­ sion remain unknown (Liu et al., 2020). An important study was conducted on whole grains, which significantly influenced blood pressure. In addition to fiber, whole-grain diets also comprise magnesium, potassium, and some protein, which can reduce systolic and diastolic blood pressures. Furthermore, whole grains increase blood concentrations of hormones such as adiponectin, which are anti-inflammatory and help in lowering blood pressure (Gupta, Meghwal, and Prabhakar, 2021). The epidemiological studies suggested that whole wheat grain eating reduces the incidence of cardiovascular diseases. In a study conducted on 822 diabetic women in the United States, results indicate that the consumption of a whole-grain-based diet is helpful in the reduction of cardiovascular disease-related mortality among diabetic women. A group of 82 subjects, who also eat three or more servings of whole-grain­ based diets per day, lower down up to 20 to 30% possibilities of heart-related diseases as compared to those who do not consume whole grains. The bran, a fraction of the whole grain, has been shown to play a significant role in reducing the incidence of cardiovascular disease (Khan et al., 2022). In a 21-day animal experiment, rats were fed either whole-wheat bread or refined bread ad libitum. The plasma cholesterol that was measured was dramatically reduced in the whole-grain-fed group while the total steroid excretion was substantially increased, indicating a positive benefit of the whole wheat diet in the prevention of cardiovascular disease. Recently, a cardioprotective mechanism has been put forward in which three impor­ tant components of a whole-grain diet are identified that are phytosterol, phytochemi­ cal, and lipidomic compounds alkylresorcinols. The combined effect of dietary fiber and phytosterol affects fat metabolism, reduces atherosclerosis activity, and improves lipid profiles in cardiac patients. At the same time, phytosterol influences many inter­ mediates of lipid metabolism and exerts high levels of antioxidant effects that regulate the vascular endothelium and finally reduce the endothelial dysfunction that promotes atherosclerosis, which is considered a major risk factor for CVD (Rosa-Sibakov, Poutanen, and Micard, 2015). Moreover, other biochemical parameters such as TAGs and LDL cholesterol were reduced, while HDL cholesterol (HDL-C) improved in whole-grain-fed rabbits. The apparent effect is ascribed to the biochemical mechanism that favors healthy effects attributed to whole wheat. The consumed dietary fibers undergo bacterial-mediated fermentation in the human large intestine and enhance the generation of SCFAs. In addition, a recent study indicated that a transient 0.4% (w/w) AR-based diet signifi­ cantly enhanced the disposal of fecal cholesterol, and this decreased the blood choles­ terol level in an HFHSD-induced mouse model. Additionally, it also decreased the rate of cholesterol absorption in the digestive tract. In addition, epidemiological studies have linked increased flavonoid consumption to a decreased risk of cardiovascular diseases and death due to cardiovascular diseases (Oishi et  al., 2015). Wheat flavonoids and intermediate metabolites may mitigate oxidative stress and inflammation by lowering down nitric oxide synthase (Enos) and reactive oxygen species (ROS) levels in endo­ thelial, while enhanced extract of whole wheat reduced Dox-induced redox stress in rat cardiac cells (Yamagata and Yamori, 2020). It is also observed that the consumption of wheat-based polyphenols and fiber grains reduce the risk of cardiovascular diseases.

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Recently, dysbiosis in the gut was held responsible for bowel inflammation that enhances the permeability of the gut membrane and further increases the risk of CVD, but the consumption of whole grains restored the natural structure of gut barri­ ers and gut microbiota because of presence of prebiotics in wheat bran. The detailed microflora-based mechanisms are still not known completely.

5.9.3.2 Stroke Stroke has caused a large number of mortality and morbidity in the developing world. The survivors of strokes often live with deformities and other serious complications. Therefore, improved diet and lifestyle are very important to reduce the incidence of stroke in the human population. A link between whole-grain consumption in the diet and a lower risk of stroke has been established. It is also observed that there is a strong connection between high blood pressure and stroke. In an epidemiological study, a diet rich in cereal fiber, vitamin K, and antioxidants and a healthy lifestyle were linked to a lower risk of stroke. An 18-year study conducted on a population of 39,053 healthy women over 45 years old, using female subjects, endorses this claim (Oh et al., 2005; Kurth et al., 2006). The risk of hemorrhagic and total stroke was found to be inversely related to DF consumption. It was noticed that the risk of stroke was lowered overall by 36%, and the risk of hemorrhagic stroke was reduced by almost 50% for those who consumed the most cereal fiber. Numerous reports concluded that both WGs and cereal fiber were probably the two dietary components that reduced the risk of stroke. But still, substantial evidence is not available and data is not cred­ ible, rather associational only. More information is required to fully comprehend the consequences of all WG-based diets, and their effects on cellular metabolism. To unravel the connection between WGs and incidence of stroke, other lifestyle factors and WG biochemical pathways must be considered, just like in the case of other dis­ eases. Furthermore, it remains to be seen whether the reduction in diseases is due to the synergetic actions of functional components or any individual component of whole grains.

5.9.4 Type II Diabetes Type II diabetes (T2D) is a serious global health problem that has a negative socio­ economic impact, particularly in developing countries. According to estimates, by 2030, 439 million people will be affected by T2D globally. In the last 20 years, the incidence of T2D in adults has been raised to 69%, especially in poor nations, and by 20% in developed countries. Recently, many scientific investigations have shown that eating whole-grain cereals-based diets is linked with a decreasing risk of T2D (Lachman et  al., 2017). Long-term studies are carried out on 90,000 women and about 45,000 men. Both studies show a nearly 30% lower possibility of the develop­ ment of T2D in subjects who consume more wheat-based dietary fiber compared to others (Salmerón et al., 1997). In a different study, it was also found that those who eat mostly refined grains and little number of whole grains were 57% more prone to develop T2D than people who consumed mostly whole grains. In addition, a 42,898­ man follow-up study by researchers found a 37% lower risk of the occurrence of type II diabetes in subjects who consumed three meals of wheat grains per day (Khan et al., 2022). These findings showed that whole-grain cereal consumption lowers the

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relative risk of T2D by 30% when combined with prospective cohort studies (Fung et  al., 2002; Y. Wang, Duan, Zhu, Fang, and He, 2019). According to randomized, controlled dietary trials conducted on human subjects and other experimental stud­ ies, whole-grain eating and the occurrence of T2D are very much associated. A diet rich in whole-grain foods also reduces postprandial (PP) concentration of insulin and plasma triglyceride levels in the blood of persons suffering from metabolic syndrome by 29 and 43%, respectively; and the findings of the study suggest that the relationship between cereal consumption and a lower risk of type-2-diabetes and cardiovascular diseases has been explained by the amount of insulin hormone and plasma TAGs after 2 hours of taking a diet (PP) (Khan et al., 2022). However, studies in this area have produced widely divergent results, which suf­ ficiently demonstrate the need for greater investigation. While the dietary fibers and phenolic acids present in whole-grain bran offer great health benefits of eating whole grains, more research is necessary to fully know the effects. More recently, the combined effect of phytic acid, phenolic acids, and Ars has been studied that reveals their contribution in regulation of blood glucose reading, insulin resistance, and hyperinsulinemia. The prescription of a 0.05% ferulic acid (FA) diet affects the activities of three main enzymes involved in the regulation of glucose metabolism, that is, glucose-6-phosphatase (G-6-pase), phosphoenolpyruvate carboxykinase (PEPCK), and glucokinase (GK) activity and insulin secretion. Among them, the first two enzymes were stimulated while the last one was inhibited by an FA-based diet (Tian et al., 2022).

5.9.5 Cancers According to World Health Organization (WHO), cancer is a cause of prolonged illness and premature death. Every year, nearly 14  million new cancer incidences and eight million deaths are reported, and the number is constantly increasing (Parascandola and Pearlman, 2022). According to a study by the World Cancer Research Foundation, eating 90 grams of whole grains per day is strongly associ­ ated with a lower incidence of cancer, particularly colorectal cancer. Consequently, it is generally recommended that people eat more whole grains and fruits and veg­ etables. The logic behind this advice is that eating whole grains may stimulate the growth of healthy intestinal microbiota that produce short-chain fatty acids, reducing the transit time of food through the gut or preventing insulin resistance (Khan et al., 2022). Dietary fiber is also significant to protect against cancers by its rapid excretion from the body via binding with carcinogens and also by regulating glycemic response. Currently, whole grains and their based products are becoming more popular among the population due to their protective roles in cancer prevention. Three major wheat components, such as phytochemicals, antioxidants, and vitamins, which fight against oxidative stress in the cellular environment, give them an anti-cancer effect. Moreover, phytochemicals in whole grains regulate cellular signal transduction processes and the behavior of cancer cells, such as their growth and death or apopto­ sis. Antioxidants in wheat bran protect normal body cells and stop the damage from oxidation at the cellular level. Therefore, it can be inferred that a variety of pheno­ lic acids can stop cancerous growth because of their potential to reduce oxidative damage to cells and organelles. The whole grain has proved effective, particularly in the case of colorectal cancer. In an experiment conducted on 25 subjects and control

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studies, a relationship has been established between whole-grain consumption and the occurrence of rectum cancer (Haas, Machado, Anton, and Silva, 2009). The results showed that eating a whole-grain-rich diet and cereal fiber was linked to a lower risk of colorectal cancer. In a population-based study of about 60,000 women, the suscep­ tibility to colorectal cancer and the consumption of whole-grain diets were related (Ringland, Arkenau, O’Connell, and Ward, 2010). The results showed that women who consume whole grains abundantly (4.5 servings/day) were less susceptible to get­ ting colon cancer in comparison to those who consumed a small number of whole grains (1.5 servings/day). It is already known that phytosterol lowers the chance of developing cancer. The potential role of phytosterol has been noticed in methylnitrosourea-fed rats. It is well known that methylnitrosourea is a cancer-causing chemical agent (Ramprasath and Awad, 2015). Furthermore, the results also revealed that eating 0.2% sitosterol in the diet for 28 weeks substantially lowered the risk of rectum cancer by up to 24% and also reduced the severity of tumor formation in methylnitrosourea-affected animals. Wheat bran is a major component of the whole grain that consists of phenolics and dietary fiber that promote the synthesis of short-chain fatty acids (SCFAs) via gut microbe fermentation (Adebo and Gabriela Medina-Meza, 2020). Generally, cancer patients have lower growth of lactobacillus, Clostridium, and Roseburia spp., but dietary fiber and phytochemicals promote their growth that plays a significant role in the repair of colon tissues and maintaining homeostasis in the digestive system (Liu et al., 2020). More recently, the individual component alkylresorcinol has been tested against colon cancer. The experiments were conducted on the cancerous cell lines, HCT-116 and HT-29, which show that bioactive components in wheat bran reduce the growth of colon cancer cells which is attributed to cellular apoptosis, autophagy, and metabolic pathways inside the endoplasmic reticulum (ER) (Y. Zhu, Conklin, Chen, Wang, and Sang, 2011). Based on many research reports, it can be inferred that eating sufficient amounts of whole grains makes a person less susceptible to cancer. But we still require more studies to find a stronger link between whole grains and lower mortality with cancers that can be attributed to their intricate molecular structure, and bound phenolic acids offer health benefits by reaching the colon mostly undigested, where they act as anti­ oxidants and anti-inflammatory agents.

5.9.6 Effect on Overall Mortality Lifestyle or noncommunicable diseases (NCDs) are responsible for the prema­ ture deaths of 41 million people (71% of total deaths) between the ages of 30 to 69 years every year in low-income countries, which mainly include cardiovascular diseases, cancers, respiratory diseases, and diabetes (“Noncommunicable diseases: Mortality”, n.d.; www.who.int/data/gho/data/themes/topics/topic-details/GHO/ ncd-mortality). Epidemiological studies reveal that individuals who consumed mostly whole grains, fruit, vegetables, and regular exercise had a 20% lower death risk than those who consumed the least bioactive-rich diets. Consequently, fewer deaths from CHD, CVD, and cancer resulted in substantially lower mortality rates. This can be endorsed by the studies conducted in Iran and the study carried out by the Atherosclerosis Risk in Communities (ARIC) Study on mixed populations (Weng et al., 2013).

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5.10 Bioavailability and Bioaccessibility of Bioactive Compounds in Wheat Grains Although the bioavailability concept was first used in the pharmaceutical industry, it is mainly applied to pharmaceutical agents that reach blood circulation after an absorption process in the human digestive system. In nutritional science, bioavail­ ability is referred to as the efficient absorption of a nutrient in the blood circulation and then its entry into the cellular systems. Many factors often decide the bioavail­ ability of nutrients, such as the compound proportion that is released of bionutrients from the food matrix and then absorbed in intestine (Angelino et  al., 2017) – for example, wheat bran, which is a rich source of bionutrients but entrapped in a very intricate interwoven network of many cell wall polysaccharides and polyphenols that are released and available after wheat bran is fine ground, hence nutrients are effi­ ciently bioavailable in the gut. It is already mentioned before that whole wheat grains and their related diets contain a large number of bioactive components which are asso­ ciated with many health benefits in the human population (Katileviciute et al., 2019). Hence, the bioavailability of bioactive compounds inside the tissues is of the utmost priority. But many factors affect the bioavailability of these bioactive compounds, directly or indirectly in the human digestive system and, finally, their absorption in the blood. There are many downstream processes for grains, including germination, farming, debranning, milling, fermentation, etc., which will be discussed next.

5.10.1 Wheat Farming The aforementioned discussion and numerous scientific investigations clearly show that genotypes influence the composition of bioactive components (phenolics and micro-nutrients) in the wheat grain, such as phenolic compounds, concentration of thiamine, riboflavin, and minerals. Additionally, farming conditions are also very cru­ cial parameters that affect the composition of wheat content. Simultaneously, it also affects the antioxidant potential and scavenging properties of phenolic compounds and nutrients. Environmental and farming conditions like production year and crop pattern, irrigation conditions, abiotic and biotic stresses, and genotypes all affect the bioactive components in a grain. In a highly significant experiment, it has been shown that the chelating potential and radical scavenging properties of 2,2-diphenyl-1-pic­ rylhydrazyl (DPPH) are affected by the environmental conditions that indirectly indi­ cate the change in the composition of bioactive compounds (Yu, Nanguet, and Beta, 2013). Furthermore, strong action of 2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) against free radicals was recorded in a crop that was grown under stress­ ful growing conditions. In winters, wheat varieties and three durum wheat varieties contain almost the same amount of phenolics. But it was also noticed that the phenolic amount of the wheat genotypes grows under organic farming, which consist of higher amounts of phenolic compounds and total antioxidant properties than when grown in conventional ways by using a large number of fertilizers and pesticides. Moreover, the composition of free and conjugated phenolic components (tocols and alkylresorcinols) is also influenced by environmental conditions (K. Zhou, Yin, and Yu, 2005). The substantial effect of farming conditions on the content of carotenoids, an important phenolic compound, is affected by environmental and genotype interactions.

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5.10.2 Germination Germination is used to enhance the nutritional composition of whole-grain products. This is attributed to the action of some endogenous enzymes which break down or metabolize large molecules into small ones, for example, monosaccharides and essen­ tial amino acids, gamma-aminobutyric acid (GABA), fat-soluble vitamins, micronu­ trients, phytochemicals, and soluble dietary fiber. Scientific investigations have shown that germinated wheat grains consist of high levels of bioactive components such as phenolic compounds, micronutrients, and antioxidant properties that provide better health benefits. To confirm these findings, wheat grains were germinated for vari­ ous periods of 24, 48, 72, and 96 hours, and then phenolic compounds, antioxidants, and related proteins and enzymes were estimated by using 2D gel electrophoresis and peptide mass fingerprinting (PMF) (Kim, Kwak, and Kim, 2018). Results show that 15 proteins/enzymes (such as glutathione-S-transferase, starch synthase, and β-glucosidase) out of 85 proteins are linked with a high potential to neutralize reac­ tive oxygen species. That capability was highest in the 96 hours germinated sample. Moreover, high amounts of phenol-based acids such as gallic acid, 4-hydroxyben­ zoic acid, vanillic acid, caffeic acid, syringic acid, ferulic acid, p-coumaric acid, and GABA (gamma-aminobutyric acid) were recorded in the germinated samples than in the control. The improvements in the antioxidant potential of germinated wheat grains were also observed in the Canadian Western Red Spring (CWRS) and Chinese wheat varieties (Chen et al., 2017).

5.10.3 Debranning After the industrial revolution, the debranning of wheat grains was started before the milling process. Debranning is a downstreaming process in which external lay­ ers of the whole wheat grain are sequentially removed by using abrasion and fric­ tion techniques. The main objectives of the debranning process are to improve the refinement of hard grains and decrease contamination from the outer layers of the grain because the outer layers of wheat grains comprise pesticides and toxic traces, elements, heavy metals, and mycotoxins that can be deleterious to health (Ficco et al., 2020). Moreover, debranning is also carried out to isolate the bioactive components from the grain to prepare nutritious food and to meet the quality parameters of refined flour. But the debranning process leaves behind a very degradative effect in terms of reduced bioactive components in debranning grains and their based foods (Barroso Lopes, Salman Posner, Alberti, and Mottin Demiate, 2022). For example, the deb­ ranning of durum wheat varieties reduced the phenolic compounds anthocyanin and polyphenols by 45 and 15%, respectively. On the other hand, nutritive and essential trace elements such as minerals were retained up to 90%, and toxic elements were reduced up to 11%. Hence, debranning is a good technology for the preparation of quality refined flour, and it is considered a better process than milling to provide bioactive compounds, low contamination, and safety of flour. The level of debran­ ning affects the mixograph properties such as mixing time, dough strength and past­ ing parameters (final, breakdown, and peak viscosity) (Ladhari et al., 2022). While cooking properties (lighter crumb and crust color) are improved at 4% of the deb­ ranning level. Recently, Chinese steamed bread (CSB) was analyzed for its sensory qualities. The results showed that bread texture, taste, and color improved up to 7%,

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but the antioxidant potential was reduced very much in the 16% degree of debranning wheat flour sample. Although the excessive debranning process is deleterious to the bioactive components in grain, the moderate level of debranning 0–5% proved highly effective to reduce microbial load up to 80.1%, and 15.82% of deoxynivalenol and aleurone layer was intact; hence, bran-associated micronutrients could be retained in the flour (Sun, Liu, Zhang, Liu, and Hou, 2022). Therefore, moderate peeling is better for economic and nutritional reasons, simultaneously reaping the benefits of milling wheat grains.

5.10.4 The Effect of Grain Milling and Grinding The milling process is a prehistoric process that was practiced in all old civilizations of the world and is used to grind starch and plant materials. Since the invention, mill­ ing technology has changed substantially and is carried out by very elaborate machin­ ery. The process of wheat milling is affected by grain hardness and biochemical factors (such as protein content), which are the most important parameters for wheat quality. Milling is also influenced by the moisture content (typically 16%) and compo­ sition of the cell wall of wheat grain before the pre-milling process, that is, tempering. Given that whole grains and whole-grains-based products offer more nutritive and health benefits than refined flour (RF), whole-wheat flour poses many quality prob­ lems that are in high demand by consumers the world over, such as functionality and quality. Moreover, whole-grain bread is low in quality, for instance, bread consisting of a lower specific volume and a denser crumb texture (Jones, Adams, Harriman, Miller, and Van der Kamp, 2015). Another factor is that the particle size of whole-wheat flour also affects food prod­ uct quality and the functionality of the wheat flour. Many studies have focused to eval­ uate the effects of milling on whole-wheat flour and its particle size and on various thermo-mechanical, and physicochemical properties by using Mixolab, Farinograph, Mixograph, and Consistograph techniques. It has been observed that flour particle size influences the damaged starch and solvent retention capacity (SRC) profiles of dough (Bressiani, Oro, and Da Silva, 2019). The effect of milling and ultrafine grinding on the nutritive values of wheat-based products such as bread, pasta, and bulgur has been discussed in various scientific investigations. This provides deep insight and offers a mixed bag of results, for exam­ ple, some reports indicate that the whole grain provides bioactive components, but at the same time, a few reports also show that the fine milling process decreases the particle size of bran and starch that improve bioaccessibility in the human digestive system and thus ensure more nutritive value (Igrejas et al., 2020). Therefore, the mill­ ing process improves the digestibility and the bioavailability of amino acids, minerals, and vitamins. Because ultrafine grinding of wheat bran improves the surface area up to three times the ultrafine bran fraction with a particle size of 30 micrometers, it releases the free and bound phenolics from the cell wall matrix, thus improving antioxidant activities from 30 to 45 mmol TEAC/kg (Rosa, Barron, Gaiani, Dufour, and Micard, 2013). Another study substantiates the fact that endogenous enzymes in the flour are inactivated, hence reducing the rancidity, breakdown of lipids, and anti­ oxidants so that refined flour is more stable as compared to whole-grain flour. Large sizes of bran particles influenced the concentration, for example, of phytic acid, the

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main anti-nutrient conjugated with most minerals due to being a strong metal chelator, Therefore, the bioavailability of iron, zinc, and calcium can be impeded in the diges­ tive system (Santos, Saraiva, Vicente, and Moldão-Martins, 2019). The milling process alone does not affect the nutritional status, but the type of milling technology itself used for milling wheat flour is also highly significant. In an important study, different types of milling methods were used for the preparation of whole-wheat flour. Then various physicochemical properties and concentrations of bioactive components were also evaluated. When comparing nutrient concentration influenced by different milling techniques, some studies show that stone milling is better than other methods such as over roller, plate, or hammer milling in respect of nutrients. In a comparison study between stone- (SWF) and roller-milling (RWF) techniques in the bread-making process, results indicate that no palpable differences were noticed in the proximate composition of the nutrients of four Bolero cv CWRS BonaVita cv Skorpion cv wheat varieties, but the RWF is proved most suitable for rheological, nutritional technological properties and gluten aggregation kinetics in terms of bread-making process (M A Pagani, Giordano, Cardone, and Pasqualone, 2020). Moreover, the extraction level is also responsible for the bioavailability of bio­ active components, which means the percentage of extraction is also important for the availability of nutrients.

5.10.5 Bread Making The bread-making industry was established in ancient civilizations. However, wheat grain and flour are used to produce a large number of food items, including bread, chapati, pasta, various types of noodles, and other food products. But there are millions of food lovers who mainly consume bread as a staple food, particularly in South Asia, Africa, and various regions of the world. Recently, consumers from all over the world are demanding bread made from whole-grain wheat flour which contributes to the health benefits of people because a major fraction of whole wheat grain, that is, bran and germ, consists of a large number of bioactive components. But now a question has emerged about bread making and its effects on the available bioactive components in whole-grain flour and their bioavailability in the human digestive system (Pagani et al., 2020). A plethora of studies has been carried out to address this particular question, ranging from flour to storage of bread and consumption. A few studies have suggested that the use of whole grains improves the nutritional quality of bread by enhancing the quantity of proteins, micronutrients, fatty acids, and both soluble and insoluble dietary fiber compared to bread produced from refined wheat flour. Moreover, both the formu­ lation and downstream processing of bread flour and the bread-making process itself affect the composition and bioavailability of micronutrients and phenolic acids in the bread and their absorption in the digestive system (Pagani et al., 2020). Bread making is a multistep process that includes dough mixing, yeast-based fer­ mentation and proofing, and baking that affect phenolic profiles and their antioxidant potential, proteins, and dietary fibers. To reap the maximum benefits of whole-grain bread and whole wheat products, it is essential to understand the mechanisms of bread-making methods that influence bioactive components (Pagani et al., 2020). Initially, flour is mixed to make the distribution of ingredients even. However, flour composition is affected by the types of genotypes and other preprocessing methods. Inside the bread, the interaction between water and other biochemical

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molecules is very crucial – for example, proteins – which leads to gluten formation which constitutes a network structure containing more cohesiveness, non-stickiness, homogeneity, and good rheological characteristics. These physicochemical proper­ ties are very important for dough formation. However, it depends upon the type of dough-making procedure and the equipment. The gluten’s viscoelasticity influ­ ences the available composition of phenolic compounds in bread because phenolic compounds are conjugated with proteins using many hydrogen bonds between the functional groups (OH) of phenolic acids and the carbonyl group of the peptide (Brouns et al., 2022). In an experiment, breads were made from four different hard wheat varieties. The quality parameters such as complete phenolics, total flavonoid content (TFC), antioxi­ dant properties, and amounts of different types of phenolic acids were measured and changed substantially. For example, the phenolic profile and antioxidant activities of whole wheat were improved. Among the three important phenolic acids, syringic acid concentration decreased but enhanced the concentration of vanillic acid and ferulic acid during the fermentation. The quantity of ferulic acid and sinapic acid ranged from 278.4 to 488.9 μg/g and from 8.6 to 159.0 μg/g, respectively (Tian et al., 2021). Another step of bread making is dough mixing, which causes the loss of up to 50% of phenolic acids, including bound ferulic acid, sinapic acid, and caffeic acid, but overall improves the bioaccessibility of bioactive components in the digestive system. Although the effects of the hydrolytic enzymes, for example, oxygenase and peroxidase, that are mixed in flour, become active after the mixing and dough mak­ ing, which are also responsible for lowering the concentration of total phenolic acid. The next important step is the leaving and fermentation, which increases the size of the bread and improves the phenolic acid content due to the fermentation process. It can be due to the activation of enzymes present in the wheat flour and fermentation causing microorganisms which act on the cell wall and thus release the bound form of phenolic acids (Dahiya, Bajaj, Kumar, Tiwari, and Singh, 2020). However, the obtained results do not show complete agreement and consistency across the literature regarding the above discussion.

5.10.6 Effect of Fermentation on the Whole Grain Fermentation is the centuries-old food-processing method that has been used for the transformation or modification of raw food materials or substrates into editable or value-added forms by using a variety of microbes in different civilizations. Generally, the fermentation process positively influences the functionality, nutritional composi­ tion, appearance, flavor, color, and textures of fermented foods that can be attributed to microbial actions. As a comparatively less intricate process, fermentation turns whole grains into editable food and increases the bioavailability of bioactive com­ ponents, especially the antioxidant properties, which are health-promoting in nature. It was also proved that the fermentation process improved the phenolic compounds because of enzymatic activities that are responsible for conjugating phenolic com­ pounds into media (Adebo and Gabriela Medina-Meza, 2020). There are two types of fermentation processes: (1) natural (also called spontane­ ous) and (2) controlled fermentation is used in whole wheat grain fermentation, but the latter proved highly beneficial for improving detoxification, organoleptic proper­ ties, aroma, texture, flavor, and thus improving bioaccessibility. There are fermented

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foods prepared from whole wheat grains, including bread, boza, sourdough bread, and tempe. In the case of whole-grain fermentation, the outer coat acts as a strong bar­ rier for amino acids and small-size sugars, which are important for the fermentation process. In an important study, TPC, TFC, and TNC were decreased because of the degradation and hydrolysis of the phenolics (Montemurro, Pontonio, Gobbetti, and Rizzello, 2019) The increase in the concentration of catechin, gallic acid, and quer­ cetin was due to the breakdown of complex phenolic compounds in Lactobacillus­ based fermentation. The production of tempe from whole grains brings about many changes, for example, enhanced antioxidant activities, water-soluble bioactive com­ pounds, small-sized peptides, and many oligosaccharides that attributed to the fer­ mentation process. Similar types of results were also reported in many experiments, where ABTS, OH-scavenging, and FCRS-RP assays were used for the estimation of antioxidants during the conversion of wheat flour into tempe (Adebo and Gabriela Medina-Meza, 2020). In whole wheat grains, most of the bioactive ingredients are centered in the bran. To improve the health benefits, exogenous bran is mixed with wheat flour in a spe­ cific ratio to make whole wheat grains, as recommended by various food agencies. But the addition of bran produced a few undesirable properties such as negative sensory quality, dough rheology, and technological properties. Furthermore, whole­ wheat flour has a low shelf-life and increases in anti-nutrient and total phenolic com­ pounds. The short shelf life is because of the breakdown of lipid-based compounds by the few hydrolytic enzymes that also lead to the rancidity of flour. To overcome these problems, a few biotechnological interventions have been suggested, such as combining germination and sourdough fermentation, which have been used in many experimental studies. Sourdough fermentation is carried out by using Lactobacillus rossiae LB5, Lactobacillus plantarum 1A7, and Lactobacillus sanfranciscensis DE9, which increase the concentration of phytic acid condensed tannins, raffinose, and trypsin inhibitory activity. While bread made from fermented sprouted flour has an enhanced protein digestibility and low starch availability, and provide high concentration of peptides, free amino acids, and γ-aminobutyric acid (Montemurro et al., 2019).

5.10.7 Enzyme Technology Given the above discussion, it is very palatable that most of the bioactive components of whole grains are trapped in the bran or outer layers of cereals. The consumption of whole grains offers bioavailability of bioactive components in the digestive sys­ tem that is affected by the entrapment of polyphenolic compounds in the cell wallbased dietary fiber, and these bioactive compounds must be released from a highly intricate network of cell wall structures. However, various processing methodologies have been applied to improve the bioaccessibility via thermal treatment, ultra-milling, and enzymatic treatment of hydrolytic enzymes, which are provided by microbial sources in fermentation, indigenously present in the flour, and by exogenous additions. In addition to polyphenolic compounds, most of the minerals are bound in the form of phytates, so it becomes essential to use food-processing techniques that improve the stability, bioavailability, and biological activity of polyphenols in the biological systems and, simultaneously, the availability of minerals (Dahiya, Bajaj, Kumar, Tiwari, and Singh, 2020).

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Currently, researchers have suggested adding a variety of enzymes, such as alpha-amy­ lase, at the mixing level to increase the properties of bread in terms of fermentable sugars. Many other enzymes, especially cell wall degrading enzymes, such as glucose oxidase, hemicellulose, phospholipase plus hemicellulose, and xylanases, are used to improve the quality of dough and bread prepared from WWF. Bran contains more arabinoxylan con­ tent than endosperm. Moreover, enzymes are more important in the whole-wheat breadmaking process. Another very important enzyme is phytases used to free the bound form of minerals from the phytase – for example, the release of calcium in the presence of ther­ mostable α-amylase. However, the bioavailability of minerals and bioactive compounds depends upon the types of fermentation and used microbes like lactic acid bacteria that provide the phytase enzymes (Gómez, Gutkoski, and Bravo-Núñez, 2020). Few studies have tried to unravel the mode of action of hydrolytic enzymes on the bran and the release of entrapped polyphenolic compounds from the cell wall. Generally, most polyphenolic compounds are bound with proteins and cell-wall poly­ saccharides (arabinoxylans), which mainly comprise xylose residues linked together by β-(1,4)-linkage and thus form a long backbone that is further joined with arabinose residues. Most of the ferulic acid is conjugated to the C(O)-5 position of arabinose. Few studies show that endo-b-(1,4)-D-xylanase application releases the xylan residues. Another enzyme, β-D-xylosidase, acts on the non-reducing end of the polymeric chain of xylose. Two other important enzymes, B-L-arabinofuranosidase and ferulic acid esterases, have been used to free arabinose and ferulic acid, respectively (Angelino et al., 2017; Tian et al., 2021). The main aim of enzymatic treatments is to reorganize wheat bran structure and release trapped compounds, for example, feruloylated oligosaccharides and feruloyl oli­ gosaccharides, which are implicated in the very important antioxidant-protecting bio­ molecules. The effects of some commercially prepared enzyme preparations, including β-glucanase, cellulase, polygalacturonase, and aminopeptidase, on wheat bran are stud­ ied. Results show that up to 50% of phenolic compounds, both free and bound forms, are released from the bran. In the same experiment, the antioxidant potential of the enzyme-treated and fermented bran is measured by using the DPPH scavenging, ABTS, DPPH, FRAB, and ROS-reducing potential assays (Tian et al., 2021). Moreover, the bioaccessibility assay was also conducted to test the TNO Intestinal Model of the diges­ tive system. Although bioaccessibility is improved in the gastrointestinal model, we still need to further test the bioaccessibility by using better model systems in animals and humans (Carbonell-Capella, Buniowska, Barba, Esteve, and Frígola, 2014).

5.11 Conclusions and Prospects Whole wheat grains are a rich source of many important nutrients and bioactive com­ ponents. Many research reports have proved that wheat bioactive components are effective to prevent lifestyle-related diseases in the human population because they all act as strong antioxidants and sources of co-enzymes and cofactors that support metabolic reactions hence improving overall human metabolism. But it remains to be seen whether all bioactive components are effective synergically or act individually to reduce the possibility of chronic diseases. In addition, there are many factors such as farming conditions, cultivars, application of fertilizers or growing organically, various types of biotic and abiotic stress, and downstream processing substantially impacting

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the quantity of bioactive compounds in the human digestive system. The food-process­ ing method such as the milling and debranning process also influenced the bioacces­ sibility and bioavailability of nutrients. For example, the milling process substantially reduced the number of vitamins and phenolic compounds present in the bran of the wheat grain. Bran is a major source of most of the vitamin- and phenol-based nutraceu­ ticals hence generally recommended for the consumption of whole-grain-based diets. The two most important food-manufacturing processes, for example, fermentation and bread-making, also affect the absorption and digestion of wheat diets although fermentation improved the nutrient content of whole-wheat flour during the breadmaking process. Few experiments palpably show that fine grinding makes available the amount of minerals and phenolic compounds in the refined flour which is a poor source of dietary fiber, which regulates the growth of beneficial microflora in the colon. The healthy microflora produces the very unique metabolites which positively regulate the host metabolism and are helpful in the prevention of modern lifestyle diseases such as obesity, metabolic syndrome, cardiovascular diseases, and cancers. Enzymes have been an unavoidable part of food sciences, so they equally were applied in the improvement of wheat-based foods – for instance, the addition of enzymes further increased the availability of dietary fibers across the large intestine hence leading to more growth of beneficial bacteria. The addition of phytase is an effective way to free more minerals from bond forms and enhanced the bioavailability of minerals without impacting the quality of bran. But in the near future, researchers need to develop effective and suitable assays to test the bioaccessibility of nutrients in humans and rats. At the same time, there is also a need to develop food-processing technologies that will help to retain the properties of grains as a whole, and, simultaneously, food must be tastier and more palatable and enjoyable in comparison to refined flour which is often used in processed foods.

BIBLIOGRAPHY Abdel-Aal, E. S. M., Young, J. C., & Rabalski, I. (2007). Identification and quantification of seed carotenoids in selected wheat species. Journal of Agricultural and Food Chemistry, 55(3), 787–794. Adebo, O. A.,  & Gabriela Medina-Meza, I. (2020). Impact of fermentation on the phe­ nolic compounds and antioxidant activity of whole cereal grains: A  mini review. Molecules (Basel, Switzerland), 25(4). https://doi.org/10.3390/molecules25040927. Ahmad, S.,  & Al-Shabib, N. A. (2020). Functional Food Products and Sustainable Health. Springer. Aloo, S.-O., Ofosu, F.-K.,  & Oh, D.-H. (2021). Effect of Germination on Alfalfa and Buckwheat: Phytochemical Profiling by UHPLC-ESI-QTOF-MS/MS, Bioactive compounds, and in-vitro studies of their diabetes and obesity-related functions. Antioxidants (Basel, Switzerland), 10(10). https://doi.org/10.3390/antiox10101613. Angelino, D., Cossu, M., Marti, A., Zanoletti, M., Chiavaroli, L., Brighenti, F., . . . Martini, D. (2017). Bioaccessibility and bioavailability of phenolic compounds in bread: A review. Food & Function, 8(7), 2368–2393. https://doi.org/10.1039/c7fo00574a. Anunciação, P. C., Cardoso, L. de M., Gomes, J. V. P., Della Lucia, C. M., Carvalho, C. W. P., Galdeano, M. C., . . . Pinheiro-Sant’Ana, H. M. (2017). Comparing sor­ ghum and wheat whole grain breakfast cereals: Sensorial acceptance and bioac­ tive compound content. Food chemistry, 221, 984–989. https://doi.org/10.1016/j. foodchem.2016.11.065.

Nutritional Composition of Wheat Grains

171

Aslam, A., Zhao, S., Lu, X., He, N., Zhu, H., Malik, A. U., .  .  . Liu, W. (2021). Highthroughput LC-ESI-MS/MS  metabolomics approach reveals regulation of metabo­ lites related to diverse functions in mature fruit of grafted watermelon. Biomolecules, 11(5). https://doi.org/10.3390/biom11050628. Azzi, A. (2007). Molecular mechanism of alpha-tocopherol action. Free Radical Biology & Medicine, 43(1), 16–21. https://doi.org/10.1016/j.freeradbiomed.2007.03.013. Bahmanyar, M. A., & Ranjbar, G. A. (2008). The role of potassium in improving growth indices and increasing amount of grain nutrient elements of wheat cultivars. Journal of Applied Sciences, 8(7), 1280–1285. Balandrán-Quintana, R. R., Mercado-Ruiz, J. N., & Mendoza-Wilson, A. M. (2015). Wheat bran proteins: A  review of their uses and potential. Food Reviews International, 31(3), 279–293. https://doi.org/10.1080/87559129.2015.1015137. Barman, A., Pandey, R. N., Singh, B., & Das, B. (2017). Manganese deficiency in wheat genotypes: Physiological responses and manganese deficiency tolerance index. Journal of Plant Nutrition, 40(19), 2691–2708. https://doi.org/10.1080/01904167.2 017.1381717. Barron, C., Surget, A., & Rouau, X. (2007). Relative amounts of tissues in mature wheat (Triticum aestivum L.) grain and their carbohydrate and phenolic acid composition. Journal of Cereal Science, 45(1), 88–96. Barroso Lopes, R., Salman Posner, E., Alberti, A.,  & Mottin Demiate, I. (2022). Pre milling debranning of wheat with a commercial system to improve flour quality. Journal of Food Science and Technology, 59(10), 3881–3887 https://doi.org/10.1007/ s13197-022-05411-6. Batifoulier, F., Verny, M. A., Chanliaud, E., Rémésy, C., & Demigné, C. (2006). Variability of B vitamin concentrations in wheat grain, milling fractions and bread products. European Journal of Agronomy, 25(2), 163–169. https://doi.org/10.1016/j.eja.2006.04.009. Biel, W., Jaroszewska, A., Stankowski, S., Sobolewska, M., & Kępińska-Pacelik, J. (2021). Comparison of yield, chemical composition and farinograph properties of common and ancient wheat grains. European food research and technology  =  Zeitschrift fur Lebensmittel-Untersuchung und -Forschung. A, 247(6), 1525–1538. https://doi. org/10.1007/s00217-021-03729-7. Borel, P., & Desmarchelier, C. (2018). Bioavailability of fat-soluble vitamins and phyto­ chemicals in humans: Effects of genetic variation. Annual Review of Nutrition, 38, 69–96. https://doi.org/10.1146/annurev-nutr-082117-051628. Boukid, F., Folloni, S., Ranieri, R.,  & Vittadini, E. (2018). A  compendium of wheat germ: Separation, stabilization and food applications. Trends in Food Science  & Technology, 78, 120–133. https://doi.org/10.1016/j.tifs.2018.06.001. Bressiani, J., Oro, T., & Da Silva, P. (2019). Influence of milling whole wheat grains and particle size on thermo-mechanical properties of flour using Mixolab. Czech Journal of Food Science, 37(4), 276–284. Brier, N. D., Gomand, S. V., Donner, E., Paterson, D., Delcour, J. A., Lombi, E.,  & Smolders, E. (2015). Distribution of minerals in wheat grains (Triticum aestivum L.) and in roller milling fractions affected by pearling. Journal of Agricultural and Food Chemistry, 63(4), 1276–1285. https://doi.org/10.1021/jf5055485. Brouns, F., Geisslitz, S., Guzman, C., Ikeda, T. M., Arzani, A., Latella, G., . . . Shewry, P. R. (2022). Do ancient wheats contain less gluten than modern bread wheat, in favour of better health? Nutrition Bulletin/BNF, 47(2), 157–167. https://doi.org/10.1111/nbu.12551. Bryden, W. L., Mollah, Y., & Gill, R. J. (1991). Bioavailability of biotin in wheat. Journal of the Science of Food and Agriculture, 55(2), 269–275. https://doi.org/10.1002/ jsfa.2740550212.

172

Wheat Science

Călinoiu, L. F., & Vodnar, D. C. (2018). Whole grains and phenolic acids: A review on bio­ activity, functionality, health benefits and bioavailability. Nutrients, 10(11). https:// doi.org/10.3390/nu10111615. Capitani, M., Mateo, C. M.,  & Nolasco, S. M. (2011). Effect of temperature and storage time of wheat germ on the oil tocopherol concentration. Brazilian Journal of Chemical Engineering, 28(2), 243–250. https://doi.org/10.1590/ S0104-66322011000200008. Carbonell-Capella, J. M., Buniowska, M., Barba, F. J., Esteve, M. J., & Frígola, A. (2014). Analytical methods for determining bioavailability and bioaccessibility of bioactive compounds from fruits and vegetables: A review. Comprehensive Reviews in Food Science and Food Safety, 13(2), 155–171. https://doi.org/10.1111/1541-4337.12049. Chapagai, S., & Fink, A. M. (2022). Cardiovascular diseases and sleep disorders in South Asians: A scoping review. Sleep Medicine, 100, 139–149. https://doi.org/10.1016/j. sleep.2022.08.008. Chen, Z., Wang, P., Weng, Y., Ma, Y., Gu, Z., & Yang, R. (2017). Comparison of pheno­ lic profiles, antioxidant capacity and relevant enzyme activity of different Chinese wheat varieties during germination. Food Bioscience, 20, 159–167. Cheng, W., Sun, Y., Fan, M., Li, Y., Wang, L.,  & Qian, H. (2022). Wheat bran, as the resource of dietary fiber: A review. Critical Reviews in Food Science and Nutrition, 62(26), 7269–7281. https://doi.org/10.1080/10408398.2021.1913399. Chooi, Y. C., Ding, C., & Magkos, F. (2019). The epidemiology of obesity. Metabolism: Clinical and Experimental, 92, 6–10. https://doi.org/10.1016/j.metabol.2018.09.005. Cilla, A., Barberá, R., López-García, G., Blanco-Morales, V., Alegría, A.,  & GarciaLlatas, G. (2019). Impact of processing on mineral bioaccessibility/bioavailabil­ ity. In Innovative Thermal and Non-Thermal Processing, Bioaccessibility and Bioavailability of Nutrients and Bioactive Compounds (pp.  209–239). Elsevier. https://doi.org/10.1016/B978-0-12-814174-8.00007-X. D’Appolonia, B. L.,  & Rayas-Duarte, P. (1994a). Wheat carbohydrates: Structure and functionality. In W. Bushuk & V. F. Rasper (Eds.), Wheat (pp. 107–127). Springer. https://doi.org/10.1007/978-1-4615-2672-8_8. Dahiya, S., Bajaj, B. K., Kumar, A., Tiwari, S. K., & Singh, B. (2020). A review on biotech­ nological potential of multifarious enzymes in bread making. Process Biochemistry, 99, 290–306. De Bruijn, W. J. C., Vincken, J.-P., Duran, K., & Gruppen, H. (2016). Mass spectromet­ ric characterization of benzoxazinoid glycosides from rhizopus-elicited wheat (Triticum aestivum) seedlings. Journal of Agricultural and Food Chemistry, 64(32), 6267–6276. https://doi.org/10.1021/acs.jafc.6b02889. Dhua, S., Kumar, K., Kumar, Y., Singh, L., & Sharanagat, V. S. (2021). Composition, char­ acteristics and health promising prospects of black wheat: A review. Trends in Food Science & Technology, 112, 780–794. https://doi.org/10.1016/j.tifs.2021.04.037. Dinelli, G., Segura-Carretero, A., Di Silvestro, R., Marotti, I., Arráez-Román, D., Benedettelli, S., . . . Fernadez-Gutierrez, A. (2011). Profiles of phenolic compounds in modern and old common wheat varieties determined by liquid chromatography coupled with time-of-flight mass spectrometry. Journal of Chromatography. A, 1218(42), 7670–7681. https://doi.org/10.1016/j.chroma.2011.05.065. Eckel, R. H., Grundy, S. M., & Zimmet, P. Z. (2005). The metabolic syndrome. The Lancet, 365(9468), 1415–1428. https://doi.org/10.1016/S0140-6736(05)66378-7. El-Naggar, A., de Neergaard, A., & El-Araby, A. (2009). Simultaneous uptake of multiple amino acids by wheat. Journal of Plant Nutrition, 32(5), 725–740.

Nutritional Composition of Wheat Grains

173

Eriksen, A. K., Brunius, C., Mazidi, M., Hellström, P. M., Risérus, U., Iversen, K. N., . . . Landberg, R. (2020). Effects of whole-grain wheat, rye, and lignan supplementa­ tion on cardiometabolic risk factors in men with metabolic syndrome: a random­ ized crossover trial. The American Journal of Clinical Nutrition, 111(4), 864–876. https://doi.org/10.1093/ajcn/nqaa026. Esposito, F., Arlotti, G., Maria Bonifati, A., Napolitano, A., Vitale, D.,  & Fogliano, V. (2005). Antioxidant activity and dietary fibre in durum wheat bran by-prod­ ucts. Food Research International, 38(10), 1167–1173. https://doi.org/10.1016/j. foodres.2005.05.002. FAO Cereal Supply and Demand Brief  |  World Food Situation  |  Food and Agriculture Organization of the United Nations. (n.d.). Retrieved April 14, 2023, from www.fao. org/worldfoodsituation/csdb/en/ Ferguson, L. R., & Harris, P. J. (1999). Protection against cancer by wheat bran: Role of dietary fibre and phytochemicals. European Journal of Cancer Prevention, 8(1), 17–25. Ficco, Donatella B. M., Borrelli, G. M., Miedico, O., Giovanniello, V., Tarallo, M., Pompa, C., .  .  . Chiaravalle, A. E. (2020). Effects of grain debranning on bioactive com­ pounds, antioxidant capacity and essential and toxic trace elements in purple durum wheats. LWT, 118, 108734. https://doi.org/10.1016/j.lwt.2019.108734. Ficco, Donatella B. M., Mastrangelo, A. M., Trono, D., Borrelli, G. M., De Vita, P., Fares, C., . . . Papa, R. (2014). The colours of durum wheat: A review. Crop and Pasture Science, 65(1), 1. https://doi.org/10.1071/CP13293. Fung, T. T., Hu, F. B., Pereira, M. A., Liu, S., Stampfer, M. J., Colditz, G. A., & Willett, W. C. (2002). Whole-grain intake and the risk of type 2 diabetes: A prospective study in men. The American Journal of Clinical Nutrition, 76(3), 535–540. https://doi. org/10.1093/ajcn/76.3.535. Gałkowska, D., Witczak, T.,  & Witczak, M. (2021). Ancient wheat and quinoa flours as ingredients for pasta dough-evaluation of thermal and rheological properties. Molecules (Basel, Switzerland), 26(22). https://doi.org/10.3390/molecules26227033. Ganji, S. H., Kamanna, V. S., & Kashyap, M. L. (2003). Niacin and cholesterol: role in cardiovascular disease (review). The Journal of Nutritional Biochemistry, 14(6), 298–305. https://doi.org/10.1016/s0955-2863(02)00284-x. Garcia Molina, M. D., Botticella, E., Beleggia, R., Palombieri, S., De Vita, P., Masci, S., . . . Sestili, F. (2021). Enrichment of provitamin A content in durum wheat grain by suppressing β-carotene hydroxylase 1 genes with a TILLING approach. TAG. Theoretical and Applied Genetics. Theoretische und Angewandte Genetik, 134(12), 4013–4024. https://doi.org/10.1007/s00122-021-03944-6. Garg, A., Sharma, A., Krishnamoorthy, P., Garg, J., Virmani, D., Sharma, T., .  .  . Sikorskaya, E. (2017). Role of niacin in current clinical practice: A systematic review. The American Journal of Medicine, 130(2), 173–187. https://doi.org/10.1016/j. amjmed.2016.07.038. Geng, P., Sun, J., Zhang, M., Li, X., Harnly, J. M.,  & Chen, P. (2016). Comprehensive characterization of C-glycosyl flavones in wheat (Triticum aestivum L.) germ using UPLC-PDA-ESI/HRMS(n) and mass defect filtering. Journal of Mass Spectrometry, 51(10), 914–930. https://doi.org/10.1002/jms.3803. Giacco, R., Costabile, G., Della Pepa, G., Anniballi, G., Griffo, E., Mangione, A., .  .  . Riccardi, G. (2014). A  whole-grain cereal-based diet lowers postprandial plasma insulin and triglyceride levels in individuals with metabolic syndrome. Nutrition, Metabolism, and Cardiovascular Diseases, 24(8), 837–844. https://doi.org/10.1016/j. numecd.2014.01.007.

174

Wheat Science

Gómez, M., Gutkoski, L. C., & Bravo-Núñez, Á. (2020). Understanding whole-wheat flour and its effect in breads: A  review. Comprehensive Reviews in Food Science and Food Safety, 19(6), 3241–3265. https://doi.org/10.1111/1541-4337.12625. Gooding, M. J., & Shewry, P. R. (2022). Wheat: Environment, Food and Health. Books. google.com. Goyer, A. (2010). Thiamine in plants: Aspects of its metabolism and functions. Phytochemistry, 71(14–15), 1615–1624. https://doi.org/10.1016/j.phytochem.2010.06.022. Guo, H., Ding, J., Liang, J., & Zhang, Y. (2021). Associations of whole grain and refined grain consumption with metabolic syndrome. A  meta-analysis of observational studies. Frontiers in Nutrition, 8, 695620. https://doi.org/10.3389/fnut.2021.695620. Gupta, R., Meghwal, M., & Prabhakar, P. K. (2021). Bioactive compounds of pigmented wheat (Triticum aestivum): Potential benefits in human health. Trends in Food Science & Technology, 110, 240–252. https://doi.org/10.1016/j.tifs.2021.02.003. Haas, P., Machado, M. J., Anton, A. A., & Silva, A. S. S. (2009). Effectiveness of whole grain consumption in the prevention of colorectal cancer: Meta-analysis of cohort studies. International Journal of Food Sciences and Nutrition, 60(6), 1–13. Hanhineva, K., Rogachev, I., Aura, A.-M., Aharoni, A., Poutanen, K., & Mykkänen, H. (2011). Qualitative characterization of benzoxazinoid derivatives in whole grain rye and wheat by LC-MS metabolite profiling. Journal of Agricultural and Food Chemistry, 59(3), 921–927. https://doi.org/10.1021/jf103612u. Hayakawa, K., Tanaka, K., Nakamura, T., & Endo, S. (2004). End use quality of waxy wheat flour in various grain-based foods. Cereal Chemistry, 81(5), 666–672. He, J., & Giusti, M. M. (2010). Anthocyanins: Natural colorants with health-promoting properties. Annual Review of Food Science and Technology, 1, 163–187. https://doi. org/10.1146/annurev.food.080708.100754. Hemery, Y., Chaurand, M., Holopainen, U., Lampi, A. M., Lehtinen, P., Piironen, V., Sadoudi, A., & Rouau, X. (2011). Potential of dry fractionation of wheat bran for the development of food ingredients, part I: Influence of ultra-fine grinding. Journal of Cereal Science, 53(1), 1–8. Hemery, Y., Lullien-Pellerin, V., Rouau, X., Abecassis, J., Samson, M. F., Åman, P., von Reding, W., Spoerndli, C., & Barron, C. (2009). Biochemical markers: efficient tools for the assessment of wheat grain tissue proportions in milling fractions. Journal of Cereal Science, 49(1), 55–64. Hemery, Y. M., Anson, N. M., Havenaar, R., Haenen, G. R., Noort, M. W., & Rouau, X. (2010). Dry-fractionation of wheat bran increases the bioaccessibility of phenolic acids in breads made from processed bran fractions. Food Research International,  43(5), 1429–1438. Heshe, G. G., Haki, G. D., Woldegiorgis, A. Z., & Gemede, H. F. (2016). Effect of conven­ tional milling on the nutritional value and antioxidant capacity of wheat types com­ mon in Ethiopia and a recovery attempt with bran supplementation in bread. Food Science & Nutrition, 4(4), 534–543. https://doi.org/10.1002/fsn3.315. Hrubša, M., Siatka, T., Nejmanová, I., Vopršalová, M., Kujovská Krčmová, L., Matoušová, K., .  .  . On Behalf of the Oemonom. (2022). Biological properties of vitamins of the B-Complex, Part 1: Vitamins B1, B2, B3, and B5. Nutrients, 14(3). https://doi. org/10.3390/nu14030484; www.fao.org/temprefdocrep/fao/meeting/018/k6021e.pdf. (n.d.). Retrieved September 2, 2022, from www.fao.org/temprefdocrep/fao/meeting/ 018/k6021e.pdf. Hu, Y., & Schmidhalter, U. (2001). Effects of salinity and macronutrient levels on micronu­ trients in wheat. Journal of Plant Nutrition, 24(2), 273–281. https://doi.org/10.1081/ PLN-100001387.

Nutritional Composition of Wheat Grains

175

Igrejas, G., Ikeda, T. M.,  & Guzmán, C. (Eds.). (2020). Wheat Quality for Improving Processing and Human Health. Cham: Springer International Publishing. https:// doi.org/10.1007/978-3-030-34163-3. Jensen, S. K., & Lauridsen, C. (2007). A-Tocopherol stereoisomers. In Vitamin E (vol. 76, pp. 281–308). Elsevier. https://doi.org/10.1016/S0083-6729(07)76010-7. Jones, J. M., Adams, J., Harriman, C., Miller, C., & Van der Kamp, J. W. (2015). Nutritional impacts of different whole grain milling techniques: A review of milling practices and existing data. Cereal Foods World, 60(3), 130–139. https://doi.org/10.1094/ CFW-60-3-0130. Jones, J. M.,  & Engleson, J. (2010). Whole grains: Benefits and challenges. Annual Review of Food Science and Technology, 1, 19–40. https://doi.org/10.1146/annurev. food.112408.132746. Katileviciute, A., Plakys, G., Budreviciute, A., Onder, K., Damiati, S.,  & Kodzius, R. (2019). A  sight to wheat bran: High value-added products. Biomolecules, 9(12). https://doi.org/10.3390/biom9120887. Kaur, N., Singh, B., Kaur, A., Yadav, M. P., Singh, N., Ahlawat, A. K., & Singh, A. M. (2021). Effect of growing conditions on proximate, mineral, amino acid, phenolic composition and antioxidant properties of wheatgrass from different wheat (Triticum aestivum L.) varieties. Food Chemistry, 341(Pt. 1), 128201. https://doi.org/10.1016/j. foodchem.2020.128201. Khan, J., Khan, M. Z., Ma, Y., Meng, Y., Mushtaq, A., Shen, Q., & Xue, Y. (2022). Overview of the composition of whole grains’ phenolic acids and dietary fibre and their effect on chronic non-communicable diseases. International Journal of Environmental Research and Public Health, 19(5). https://doi.org/10.3390/ijerph19053042. Kim, M. J., Kwak, H. S.,  & Kim, S. S. (2018). Effects of germination on protein, γ-aminobutyric acid, phenolic acids, and antioxidant capacity in wheat. Molecules (Basel, Switzerland), 23(9). https://doi.org/10.3390/molecules23092244. Kopelman, P. G. (2000). Obesity as a medical problem. Nature, 404(6778), 635–643. https://doi.org/10.1038/35007508. Ktenioudaki, A., Alvarez-Jubete, L.,  & Gallagher, E. (2015). A  review of the processinduced changes in the phytochemical content of cereal grains: The breadmaking process. Critical Reviews in Food Science and Nutrition, 55(5), 611–619. https://doi. org/10.1080/10408398.2012.667848. Kumar, N.,  & Pruthi, V. (2014). Potential applications of ferulic acid from natural sources. Biotechnology Reports (Amsterdam, Netherlands), 4, 86–93. https://doi.org/10.1016/ j.btre.2014.09.002. Kurth, T., Moore, S. C., Gaziano, J. M., Kase, C. S., Stampfer, M. J., Berger, K., & Buring, J. E. (2006). Healthy lifestyle and the risk of stroke in women. Archives of Internal Medicine, 166(13), 1403–1409. Lachman, J., Martinek, P., Kotíková, Z., Orsák, M., & Šulc, M. (2017). Genetics and chem­ istry of pigments in wheat grain – A review. Journal of Cereal Science, 74, 145–154. https://doi.org/10.1016/j.jcs.2017.02.007. Ladhari, A., Corrado, G., Rouphael, Y., Carella, F., Nappo, G. R., Di Marino, C., .  .  . Palatucci, D. (2022). Chemical, functional, and technological features of grains, brans, and semolina from purple and red durum wheat landraces. Foods, 11(11). https://doi.org/10.3390/foods11111545. Landberg, R., Hanhineva, K., Tuohy, K., Garcia-Aloy, M., Biskup, I., Llorach, R., .  .  . Kolehmainen, M. (2019). Biomarkers of cereal food intake. Genes & Nutrition, 14, 28. https://doi.org/10.1186/s12263-019-0651-9.

176

Wheat Science

Lei, L., Chen, J., Liu, Y., Wang, L., & Zhao, G. (2018). Dietary wheat bran oil is equally as effective as rice bran oil in reducing plasma cholesterol. Journal of Agricultural and Food Chemistry, 66(11), 2765–2774. Leváková, Ľ., & Lacko-Bartošová, M. (2017). Phenolic acids and antioxidant activity of wheat species: A review. Agriculture (Pol’nohospodárstvo), 63(3), 92–101. https:// doi.org/10.1515/agri-2017-0009. Li, L., Shewry, P. R.,  & Ward, J. L. (2008). Phenolic acids in wheat varieties in the HEALTHGRAIN diversity screen.  Journal of Agricultural and Food Chemistry,  56(21), 9732–9739. Liang, Q., Wang, K., Shariful, I., Ye, X., & Zhang, C. (2020). Folate content and retention in wheat grains and wheat-based foods: Effects of storage, processing, and cooking methods. Food Chemistry, 333, 127459. https://doi.org/10.1016/j.foodchem.2020. 127459. Likes, R., Madl, R. L., Zeisel, S. H., & Craig, S. A. S. (2007). The betaine and choline content of a whole wheat flour compared to other mill streams. Journal of Cereal Science, 46(1), 93–95. https://doi.org/10.1016/j.jcs.2006.11.002. Lineback, D. R., & Rasper, V. F. (1988). Wheat carbohydrates. In Y. Pomeranz Wheat: Chemistry and Technology (vol. I., 3rd ed., pp. 277–372). American Association of cereals chemists, St Paul Minnesota, USA. Liu, J., Yu, L. L., & Wu, Y. (2020). Bioactive components and health beneficial proper­ ties of whole wheat foods. Journal of Agricultural and Food Chemistry, 68(46), 12904–12915. https://doi.org/10.1021/acs.jafc.0c00705. Liyana-Pathirana, C. M., & Shahidi, F. (2006). Importance of insoluble-bound phenolics to antioxidant properties of wheat. Journal of Agricultural and Food Chemistry, 54(4), 1256–1264. https://doi.org/10.1021/jf052556h. Lu, Y., Lv, J., Yu, L., Fletcher, A., Costa, J., Yu, L. and Luthria, D. (2014). Phytochemical composition and antiproliferative activities of bran fraction of ten Maryland-grown soft winter wheat cultivars: Comparison of different radical scavenging assays. Journal of Food Composition and Analysis, 36(1–2), 51–58. Ma, D., Wang, C., Feng, J., & Xu, B. (2021). Wheat grain phenolics: A review on com­ position, bioactivity, and influencing factors. Journal of the Science of Food and Agriculture, 101(15), 6167–6185. https://doi.org/10.1002/jsfa.11428. Ma, D., Xu, B., Feng, J., Hu, H., Tang, J., Yin, G., . . . Wang, C. (2022). Dynamic metabolo­ mics and transcriptomics analyses for characterization of phenolic compounds and their biosynthetic characteristics in wheat grain. Frontiers in Nutrition, 9, 844337. https://doi.org/10.3389/fnut.2022.844337. Mansour, A., Hosseini, S., Larijani, B., Pajouhi, M., & Mohajeri-Tehrani, M. R. (2013). Nutrients related to GLP1 secretory responses. Nutrition, 29(6), 813–820. https:// doi.org/10.1016/j.nut.2012.11.015. Mateo Anson, N., Hemery, Y. M., Bast, A., & Haenen, G. R. M. M. (2012). Optimizing the bioactive potential of wheat bran by processing. Food & Function, 3(4), 362–375. https://doi.org/10.1039/c2fo10241b. Matus-Cádiz, M. A., Daskalchuk, T. E., Verma, B., Puttick, D., Chibbar, R. N., Gray, G. R., . . . Hucl, P. (2008). Phenolic compounds contribute to dark bran pigmentation in hard white wheat. Journal of Agricultural and Food Chemistry, 56(5), 1644–1653. https://doi.org/10.1021/jf072970c. McGrath, L.,  & Fernandez, M.-L. (2022). Plant-based diets and metabolic syndrome: Evaluating the influence of diet quality. Journal of Agriculture and Food Research, 9, 100322. https://doi.org/10.1016/j.jafr.2022.100322.

Nutritional Composition of Wheat Grains

177

McKeown, N. M., Marklund, M., Ma, J., Ross, A. B., Lichtenstein, A. H., Livingston, K. A., Jacques, P. F., Rasmussen, H. M., Blumberg, J. B. & Chen, C. Y. O. (2016). Comparison of plasma alkylresorcinols (AR) and urinary AR metabolites as bio­ markers of compliance in a short-term, whole-grain intervention study. European Journal of Nutrition, 55, 1235–1244. McMahon, R. J. (2002). Biotin in metabolism and molecular biology. Annual Review of Nutrition, 22, 221–239. https://doi.org/10.1146/annurev.nutr.22.121101.112819. Melini, V., Melini, F., Luziatelli, F., & Ruzzi, M. (2020). Functional ingredients from agri­ food waste: Effect of inclusion thereof on phenolic compound content and bioac­ cessibility in bakery products. Antioxidants (Basel, Switzerland), 9(12). https://doi. org/10.3390/antiox9121216. Merlino, M., Leroy, P., Chambon, C.,  & Branlard, G. (2009). Mapping and proteomic analysis of albumin and globulin proteins in hexaploid wheat kernels (Triticum aes­ tivum L.). TAG. Theoretical and Applied Genetics. Theoretische und Angewandte Genetik, 118(7), 1321–1337. https://doi.org/10.1007/s00122-009-0983-8. Mills, E. N. C., Wellner, N., Salt, L. A., Robertson, J., & Jenkins, J. A. (2020). Wheat proteins and bread quality. In Stanley P. Cauvain, Breadmaking (pp. 109–135). Woodhead Publishing. Montemurro, M., Pontonio, E., Gobbetti, M., & Rizzello, C. G. (2019). Investigation of the nutritional, functional and technological effects of the sourdough fermentation of sprouted flours. International Journal of Food Microbiology, 302, 47–58. https:// doi.org/10.1016/j.ijfoodmicro.2018.08.005. Niba, L. L.,  & Niba, S. N. (2003). Role of non-digestible carbohydrates in colon cancer protection. Nutrition  & Food Science, 33(1), 28–33. https://doi. org/10.1108/00346650310459545. Nićiforović, N., & Abramovič, H. (2014). Sinapic acid and its derivatives: Natural sources and bioactivity. Comprehensive Reviews in Food Science and Food Safety, 13(1), 34–51. https://doi.org/10.1111/1541-4337.12041. Noncommunicable Diseases: Mortality. (n.d.). Retrieved September 5, 2022, from www. who.int/data/gho/data/themes/topics/topic-details/GHO/ncd-mortality Noort, M. W., van Haaster, D., Hemery, Y., Schols, H. A., & Hamer, R. J. (2010). The effect of particle size of wheat bran fractions on bread quality–Evidence for fibre–protein interactions. Journal of Cereal Science, 52(1), 59–64. Oduro-Obeng, H., Apea-Bah, F. B., Wang, K., Fu, B. X., & Beta, T. (2022). Effect of cook­ ing duration on carotenoid content, digestion and potential absorption efficiencies among refined semolina and whole wheat pasta products. Food & Function, 13(11), 5953–5970. https://doi.org/10.1039/d2fo00611a. Ogden, C. L., Yanovski, S. Z., Carroll, M. D., & Flegal, K. M. (2007). The epidemiol­ ogy of obesity. Gastroenterology, 132(6), 2087–2102. https://doi.org/10.1053/j. gastro.2007.03.052. Oh, K., Hu, F. B., Cho, E., Rexrode, K. M., Stampfer, M. J., Manson, J. E., Liu, S., & Willett, W. C. (2005). Carbohydrate intake, glycemic index, glycemic load, and dietary fiber in relation to risk of stroke in women. American Journal of Epidemiology, 161(2), 161–169. Ohrvik, V. E.,  & Witthoft, C. M. (2011). Human folate bioavailability. Nutrients, 3(4), 475–490. https://doi.org/10.3390/nu3040475. Oishi, K., Yamamoto, S., Itoh, N., Nakao, R., Yasumoto, Y., Tanaka, K., .  .  . TakanoIshikawa, Y. (2015). Wheat alkylresorcinols suppress high-fat, high-sucrose dietinduced obesity and glucose intolerance by increasing insulin sensitivity and cholesterol excretion in male mice. The Journal of Nutrition, 145(2), 199–206. https://doi.org/10.3945/jn.114.202754.

178

Wheat Science

Pagani, M. A., Giordano, D., Cardone, G., Pasqualone, A., Casiraghi, M. C., Erba, D., . . . Marti, A. (2020). Nutritional features and bread-making performance of whole­ wheat: Does the milling system matter? Foods, 9(8), 1035–1043. Panato, A., Antonini, E., Bortolotti, F., & Ninfali, P. (2017). The histology of grain cary­ opses for nutrient location: a comparative study of six cereals. International Journal of Food Science & Technology, 52(5), 1238–1245. https://doi.org/10.1111/ijfs.13390. Parascandola, M., & Pearlman, P. C. (2022). The development of global cancer research at the United States National Cancer Institute. Journal of the National Cancer Institute, 114(9), 1228–1237. Parker, M. L., Ng, A., & Waldron, K. W. (2005). The phenolic acid and polysaccharide composition of cell walls of bran layers of mature wheat (Triticum aestivum L. cv. Avalon) grains. Journal of the Science of Food and Agriculture, 85(15), 2539–2547. Paznocht, L., Kotíková, Z., Orsák, M., Lachman, J., & Martinek, P. (2019). Carotenoid changes of colored-grain wheat flours during bun-making. Food chemistry, 277, 725–734. https://doi.org/10.1016/j.foodchem.2018.11.019. Pehlivan Karakas, F., Keskin, C. N., Agil, F., & Zencirci, N. (2021). Profiles of vitamin B and E in wheat grass and grain of einkorn (Triticum monococcum spp. Monococcum), emmer (Triticum dicoccum ssp. Dicoccum Schrank.), durum (Triticum durum Desf.), and bread wheat (Triticum aestivum L.) cultivars by LC-ESI-MS/MS analy­ sis. Journal of Cereal Science, 98, 103177. https://doi.org/10.1016/j.jcs.2021.103177. Poutanen, K. S., Kårlund, A. O., Gómez-Gallego, C., Johansson, D. P., Scheers, N. M., Marklinder, I. M., .  .  . Landberg, R. (2022). Grains—a major source of sustain­ able protein for health. Nutrition Reviews, 80(6), 1648–1663. https://doi.org/10.1093/ nutrit/nuab084. Prasoodanan P. K., V., Sharma, A. K., Mahajan, S., Dhakan, D. B., Maji, A., Scaria, J., & Sharma, V. K. (2021). Western and non-western gut microbiomes reveal new roles of Prevotella in carbohydrate metabolism and mouth-gut axis. Npj Biofilms and Microbiomes, 7(1), 77. https://doi.org/10.1038/s41522-021-00248-x. Prinsen, P., Gutierrez, A., Faulds, C., & Del Rio, J. C. (2014). A comprehensive study of valuable lipophilic phytochemicals in wheat bran. Journal of Agricultural and Food Chemistry, 62(7), 1664–1673. https://doi.org/10.1021/jf404772b. Ramprasath, V. R., & Awad, A. B. (2015). Role of Phytosterols in Cancer Prevention and Treatment. Journal of AOAC International, 98(3), 735–738. https://doi.org/10.5740/ jaoacint.SGERamprasath. Rinaldi, V. E. A., Ng, P. K. W., & Bennink, M. R. (2000). Effects of extrusion on dietary fiber and isoflavone contents of wheat extrudates enriched with wet okara. Cereal Chemistry, 77(2), 237–240. Ringland, C. L., Arkenau, H. T., O’Connell, D. L., & Ward, R. L. (2010). Second primary colorectal cancers (SPCRCs): experiences from a large Australian Cancer Registry. Annals of Oncology, 21(1), 92–97. https://doi.org/10.1093/annonc/mdp288. Rosa, N. N., Barron, C., Gaiani, C., Dufour, C., & Micard, V. (2013). Ultra-fine grinding increases the antioxidant capacity of wheat bran. Journal of cereal science, 57(1), 84–90. https://doi.org/10.1016/j.jcs.2012.10.002. Rosa-Sibakov, N., Poutanen, K., & Micard, V. (2015). How does wheat grain, bran and aleurone structure impact their nutritional and technological properties? Trends in food science & technology, 41(2), 118–134. https://doi.org/10.1016/j.tifs.2014.10.003. Saini, P., Kumar, N., Kumar, S., Mwaurah, P. W., Panghal, A., Attkan, A. K., . . . Singh, V. (2021). Bioactive compounds, nutritional benefits and food applications of col­ ored wheat: a comprehensive review. Critical reviews in food science and nutrition, 61(19), 3197–3210. https://doi.org/10.1080/10408398.2020.1793727.

Nutritional Composition of Wheat Grains

179

Saleh, A. S. M., Wang, P., Wang, N., Yang, S., & Xiao, Z. (2019). Technologies for enhance­ ment of bioactive components and potential health benefits of cereal and cereal-based foods: Research advances and application challenges. Critical reviews in food sci­ ence and nutrition, 59(2), 207–227. https://doi.org/10.1080/10408398.2017.1363711. Salmerón, J., Manson, J. E., Stampfer, M. J., Colditz, G. A., Wing, A. L., & Willett, W. C. (1997). Dietary fiber, glycemic load, and risk of non-insulin-dependent diabe­ tes mellitus in women. The Journal of the American Medical Association, 277(6), 472–477. https://doi.org/10.1001/jama.1997.03540300040031. Samson, S. L., & Garber, A. J. (2014). Metabolic syndrome. Endocrinology and Metabolism Clinics of North America, 43(1), 1–23. https://doi.org/10.1016/j.ecl.2013.09.009. Sankar, R. (n.d.). The Comprehensive Review on Fat Soluble Vitamins. Santos, D. I., Saraiva, J. M. A., Vicente, A. A., & Moldão-Martins, M. (2019). Methods for determining bioavailability and bioaccessibility of bioactive compounds and nutrients. In Innovative Thermal and Non-Thermal Processing, Bioaccessibility and Bioavailability of Nutrients and Bioactive Compounds (pp. 23–54). Elsevier. https://doi.org/10.1016/B978-0-12-814174-8.00002-0. Sharma, I., Tyagi, B. S., & Singh, G. (2015). Enhancing wheat production-A global per­ spective. Indian Journal of. Sharma, M., Sandhir, R., Singh, A., Kumar, P., Mishra, A., Jachak, S., .  .  . Roy, J. (2016). Comparative Analysis of Phenolic Compound Characterization and Their Biosynthesis Genes between Two Diverse Bread Wheat (Triticum aestivum) Varieties Differing for Chapatti (Unleavened Flat Bread) Quality. Frontiers in plant science, 7, 1870. https://doi.org/10.3389/fpls.2016.01870. Shavit, R., Batyrshina, Z. S., Dotan, N., & Tzin, V. (2018). Cereal aphids differently affect benzoxazinoid levels in durum wheat. Plos One, 13(12), e0208103. https://doi. org/10.1371/journal.pone.0208103. Shevkani, K., Singh, N., & Bajaj, R. (2017). Wheat starch production, structure, function­ ality and applications—a review. International Journal of . . . . Shewry, P. R., & Hey, S. J. (2015). The contribution of wheat to human diet and health. Food and Energy Security, 4(3), 178–202. https://doi.org/10.1002/fes3.64. Shewry, P. R., Van Schaik, F., Ravel, C., Charmet, G., Rakszegi, M., Bedo, Z., & Ward, J. L. (2011). Genotype and environment effects on the contents of vitamins B1, B2, B3, and B6 in wheat grain. Journal of Agricultural and Food Chemistry, 59(19), 10564–10571. https://doi.org/10.1021/jf202762b. Singla, R. K., Dubey, A. K., Garg, A., Sharma, R. K., Fiorino, M., Ameen, S. M., .  .  . Al-Hiary, M. (2019). Natural polyphenols: chemical classification, definition of classes, subcategories, and structures. Journal of AOAC International, 102(5), 1397–1400. https://doi.org/10.5740/jaoacint.19-0133. Stanger, O., Fowler, B., Piertzik, K., Huemer, M., Haschke-Becher, E., Semmler, A., . . . Linnebank, M. (2009). Homocysteine, folate and vitamin B12 in neuropsychiatric dis­ eases: review and treatment recommendations. Expert Review of Neurotherapeutics, 9(9), 1393–1412. https://doi.org/10.1586/ern.09.75. Sun, Y., Liu, Y., Zhang, J., Liu, J., & Hou, H. (2022). Effects of wheat debranning on the sensory quality and antioxidant activity of Chinese steamed bread. Cereal Chemistry. Suttie, J. W. (1992). Vitamin K and human nutrition. Journal of the American Dietetic Association, 92(5), 585–590. Syauqy, A., Hsu, C.-Y., Rau, H.-H., & Chao, J. C.-J. (2018). Association of Dietary Patterns with Components of Metabolic Syndrome and Inflammation among Middle-Aged and Older Adults with Metabolic Syndrome in Taiwan. Nutrients, 10(2). https://doi. org/10.3390/nu10020143.

180

Wheat Science

Tahiliani, A. G., & Beinlich, C. J. (1991). Pantothenic acid in health and disease. Vitamins and Hormones, 46, 165–228. Thakur, K., Tomar, S. K., Singh, A. K., Mandal, S., & Arora, S. (2017). Riboflavin and health: A  review of recent human research. Critical reviews in food science and nutrition, 57(17), 3650–3660. https://doi.org/10.1080/10408398.2016.1145104. Tian, W., Chen, G., Tilley, M., & Li, Y. (2021). Changes in phenolic profiles and antioxi­ dant activities during the whole wheat bread-making process. Food chemistry, 345, 128851. https://doi.org/10.1016/j.foodchem.2020.128851. Tian, W., Zheng, Y., Wang, W., Wang, D., Tilley, M., Zhang, G., .  .  . Li, Y. (2022). A comprehensive review of wheat phytochemicals: From farm to fork and beyond. Comprehensive Reviews in Food Science and Food Safety, 21(3), 2274–2308. https:// doi.org/10.1111/1541-4337.12960. Titcomb, T. J., Sheftel, J., Sowa, M., Gannon, B. M., Davis, C. R., Palacios-Rojas, N., & Tanumihardjo, S. A. (2018). Β-Cryptoxanthin and zeaxanthin are highly bioavail­ able from whole-grain and refined biofortified orange maize in humans with optimal vitamin A status: a randomized, crossover, placebo-controlled trial. The American Journal of Clinical Nutrition, 108(4), 793–802. https://doi.org/10.1093/ajcn/nqy134. Tufarelli, V., Casalino, E., D’Alessandro, A. G., & Laudadio, V. (2017). Dietary pheno­ lic compounds: biochemistry, metabolism and significance in animal and human health. Current Drug Metabolism, 18(10), 905–913. https://doi.org/10.2174/138920 0218666170925124004. Turnbull, K. M., & Rahman, S. (2002). Endosperm texture in wheat. Journal of cereal science, 36(3), 327–337. https://doi.org/10.1006/jcrs.2002.0468. Venegas, J., Guttieri, M. J., & Jr, J. B. (2022). Genetic architecture of the high-inorganic phosphate phenotype derived from a low-phytate mutant in winter wheat. Crop . . . . Wang, M., Kong, F., Liu, R., Fan, Q., & Zhang, X. (2020). Zinc in wheat grain, process­ ing, and food. Frontiers in nutrition, 7, 124. https://doi.org/10.3389/fnut.2020.00124. Wang, T., & Johnson, L. A. (2001). Refining high-free fatty acid wheat germ oil. Journal of the American Oil Chemists’ Society, 78(1), 71–76. https://doi.org/10.1007/ s11746-001-0222-2. Wang, Y., Duan, Y., Zhu, L., Fang, Z., & He, L. (2019). Whole grain and cereal fiber intake and the risk of type 2 diabetes: a meta-analysis. International Journal of . . . . Weng, L.-C., Steffen, L. M., Szklo, M., Nettleton, J., Chambless, L.,  & Folsom, A. R. (2013). A  diet pattern with more dairy and nuts, but less meat is related to lower risk of developing hypertension in middle-aged adults: The Atherosclerosis Risk in Communities (ARIC) study. Nutrients, 5(5), 1719–1733. https://doi.org/10.3390/ nu5051719. Wieser, H., Koehler, P.,  & Scherf, K. A. (2020). The two faces of wheat. Frontiers in Nutrition, 7, 517313. https://doi.org/10.3389/fnut.2020.517313. Wikipedia Contributors. (2022, May  31). Phytochemical. In Wikipedia, The Free Encyclopedia. Retrieved November 18, 2022, from https://en.wikipedia.org/w/index. php?title=Phytochemical&oldid=1090806218 Witkamp, R. F. (2022). Bioactive components in traditional foods aimed at health pro­ motion: A route to novel mechanistic insights and lead molecules? Annual Review of Food Science and Technology, 13, 315–336. https://doi.org/10.1146/annurev­ food-052720-092845. Xu, Y., An, D., Li, H., & Xu, H. (2011). Review: Breeding wheat for enhanced micronu­ trients. Canadian Journal of Plant Science, 91(2), 231–237. https://doi.org/10.4141/ CJPS10117.

Nutritional Composition of Wheat Grains

181

Yamagata, K., & Yamori, Y. (2020). Inhibition of endothelial dysfunction by dietary flavo­ noids and preventive effects against cardiovascular disease. Journal of Cardiovascular Pharmacology, 75(1), 1–9. https://doi.org/10.1097/FJC.0000000000000757. Yao, W., Gong, Y., Li, L., Hu, X., & You, L. (2022). The effects of dietary fibers from rice bran and wheat bran on gut microbiota: An overview. Food Chemistry: X, 13, 100252. https://doi.org/10.1016/j.fochx.2022.100252. Yoshida, Y.,  & Niki, E. (2003). Antioxidant effects of phytosterol and its components. Journal of Nutritional Science and Vitaminology, 49(4), 277–280. Younas, A., Sadaqat, H. A., Kashif, M., Ahmed, N., & Farooq, M. (2020). Combining abil­ ity and heterosis for grain iron biofortification in bread wheat. Journal of the Science of Food and Agriculture, 100(4), 1570–1576. https://doi.org/10.1002/jsfa.10165. Yu, L., Nanguet, A. L., & Beta, T. (2013). Comparison of antioxidant properties of refined and whole wheat flour and bread. Antioxidants, 2(4), 370–383. Zhang, Y., Song, Q., Yan, J., Tang, J., Zhao, R., Zhang, Y., . . . Ortiz-Monasterio, I. (2010). Mineral element concentrations in grains of Chinese wheat cultivars. Euphytica, 174(3), 303–313. https://doi.org/10.1007/s10681-009-0082-6. Zhao, F. J., Su, Y. H., Dunham, S. J., Rakszegi, M., Bedo, Z., McGrath, S. P., & Shewry, P. R. (2009). Variation in mineral micronutrient concentrations in grain of wheat lines of diverse origin. Journal of Cereal Science, 49(2), 290–295. https://doi. org/10.1016/j.jcs.2008.11.007. Zhou, K., Laux, J. J., & Yu, L. (2004). Comparison of Swiss red wheat grain and fractions for their antioxidant properties. Journal of Agricultural and Food Chemistry, 52(5), 1118–1123. Zhou, K., Yin, J. J.,  & Yu, L. (2005). Phenolic acid, tocopherol and carotenoid com­ positions, and antioxidant functions of hard red winter wheat bran. Journal of Agricultural and Food Chemistry, 53(10), 3916–3922. Zhou, L., Hu, S., Rong, S., Mo, X., Wang, Q., Yin, J., . . . Liu, L. (2022). DHPPA, a major plasma alkylresorcinol metabolite reflecting whole-grain wheat and rye intake, and risk of metabolic syndrome: a case-control study. European Journal of Nutrition, 61(6), 3247–3254. https://doi.org/10.1007/s00394-022-02880-5. Zhu, H., Liu, S., Yao, L., Wang, L., & Li, C. (2019). Free and bound phenolics of buck­ wheat varieties: HPLC characterization, antioxidant activity, and inhibitory potency towards α-glucosidase with molecular docking analysis. Antioxidants (Basel, Switzerland), 8(12). https://doi.org/10.3390/antiox8120606. Zhu, Y., Conklin, D. R., Chen, H., Wang, L., & Sang, S. (2011). 5-alk(en)ylresorcinols as the major active components in wheat bran inhibit human colon cancer cell growth. Bioorganic  & Medicinal Chemistry, 19(13), 3973–3982. https://doi.org/10.1016/j. bmc.2011.05.025.

6 Wheat-Based Anti-Nutritional Factors and Their Reduction Strategies An Overview Vanita Pandey, Ajeet Singh, Neha Patwa, Ankush,

Om Prakash Gupta, Gopalareddy K., Sunil Kumar,

Anuj Kumar, Sewa Ram, and Gyanendra Pratap Singh

CONTENTS

6.1

Introduction.................................................................................................... 184

6.1.1 Anti-Nutritional Factors .................................................................... 184

6.1.2 Antinutrients and Human Health ...................................................... 186

6.1.3 Anti-Nutritional Factors in Wheat .................................................... 187

6.1.3.1 Phytic Acid (PA) ................................................................ 187

6.1.3.1.1 Methods for Estimation of Phytic Acid (PA) ..... 188

6.1.3.1.2 Measures for Reducing Phytic Acid ............... 189

6.1.3.1.2.1 Application of Phytase ............. 189

6.1.3.1.2.2 Screening of Micronutrient

Dense Germplasm .................... 190

6.1.3.1.2.3 Molecular Technologies for

PA Reduction............................ 190

6.1.3.1.2.3.1 Production of

Mutants with

Low Phytic

Acid (LPA)

Content............. 190

6.1.3.1.2.3.2 Targeting

Phytic Acid

Pathway Genes... 191

6.1.3.2 Oxalates ............................................................................. 191

6.1.3.3 Enzyme Inhibitors.............................................................. 192

6.1.3.3.1 Trypsin Inhibitors ........................................... 193

6.1.3.4 Phenolic Compounds ......................................................... 195

6.1.3.5 Tannins............................................................................... 195

6.1.3.6 Haemagglutinins and Lectins ............................................ 196

6.1.3.7 Alkaloids............................................................................ 196

6.1.3.7.1 Anti-Nutritional Effects of Alkaloids ............. 197

6.1.3.8 Saponins............................................................................. 197

DOI: 10.1201/9781003307938-6

183

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6.2

Strategies for the Reduction of Anti-Nutrients .............................................. 199

6.2.1 Physical Methods............................................................................... 199

6.2.1.1 Autoclaving and Heat treatment ........................................ 199

6.2.1.2 Milling ...............................................................................200

6.2.1.3 Soaking ..............................................................................200

6.2.2 Chemical Methods............................................................................. 201

6.2.2.1 Gamma Radiation .............................................................. 201

6.2.2.2 Fermentation ......................................................................202

6.2.3 Biotechnological Interventions.......................................................... 203

6.3 Role of Enhancers/Promoters in Combating Anti-Nutritional Factors .........204

6.3.1 Role of Ascorbic Acid (AA) as a Bio-Enhancer................................ 205

6.3.2 Effect of Ascorbic Acid on non-heme Iron Absorption in Humans ....... 205

6.3.3 Limitations of Food Fortification with Ascorbic Acid......................206

6.4 Conclusion......................................................................................................206

6.5 Future Prospects.............................................................................................206

References................................................................................................................207

6.1 Introduction Cereals such as rice, wheat, and maize are staple food crops providing food and nutrition to human population across the globe. Cereal grains are vital for human nutrition providing adequate amounts of carbohydrates, protein, vitamins, minerals, and very essential dietary fiber required for the maintenance of growth and development (Nadeem et  al.,  2010). Consumption of whole-grain foods is associated with the prevention of several lifestyle disorders such as cardiovascular diseases (Jacobs and Gallaher, 2004), type II diabetes (Murtaugh et al., 2003) as well as few types of cancers (Larsson et al., 2005). Wheat (Triticum aestivum L.), a major cereal grain, is part of daily diet of approximately one-third of global populace. A very versatile crop, wheat is grown in nearly every region of the six continents with roughly 777  million-tones production (FAOSTAT,  2022). Wheat is a nutritive cereal crop with a good composition of essential macronutrients like carbohydrates, proteins, and fats and, additionally, micronutrients like vitamins and minerals (FAO 2018a, b). In the case of cereal-based diets, wheat is a major provider of dietary energy and protein to its consumers globally. Wheat is a vital crop in terms of production and consumption across the world (FAO, 2009). In recent times, wheat-based products have received widespread interest in the global consumer market as well as from the food companies due to their superior nutritional profile. Cereals in general contain lower ratio of protein in comparison to carbohydrates. Wheat flour is made up of 87% carbohydrates and nearly 11% protein, in comparison to legumes and millets which have a higher protein content (Kavitha and Parimalavalli, 2014; Malik 2015). Wheat like other cereals is limiting in essential amino acid lysine, which is present in sufficient quanti­ ties in legumes. A possible solution can be supplementing wheat flour with legumes to enhance lysine as well as other proteins (Katina et al., 2005; Awolu et al., 2017).

6.1.1 Anti-Nutritional Factors Antinutrients or anti-nutritional factors (ANFs) are chiefly substances or compounds, which impede the absorption or assimilation of nutrients, thus reducing nutrient intake,

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185

digestion, and utilization, additionally causing adverse health effects. Antinutrients are naturally synthesized by several plants and hence are commonly linked with raw, vegan, or plant-based diets (Gemede and Ratta, 2014). Consumption of antinutrients may sometimes cause adverse effects like nutritional deficiencies,  bloating, nausea, rashes, and headaches. (Essack et  al., 2017), while sensitivity to ANFs may differ in people and several times use of sufficient food-processing techniques can initially reduce its content (Soetan and Oyewole, 2009). ANFs once introduced or consumed cannot be eliminated from the body. In order to study the effects or symptoms pro­ duced by a particular ANF, removing and reintroducing the ANF through the specific food can be an effective strategy. Several studies are being carried out in this regard to study the biochemical effects of the ANFs on human body (Aletor, 1993; Petroski and Minich, 2020). Several secondary metabolites, behaving as ANFs, may elicit danger­ ous biological response; however, numerous of them are commonly utilized as phar­ maceutical drug or have role in nutrition (Soetan, 2008). However, these ANFs are generally vital to plant and may have a role in plant growth, development, defense, etc. ANFs in general are found in high concentration in beans, grains, nuts, and legumes in comparison to roots, leaves, and fruits in the plants they occur. Several ANFs are found in plants having toxic potential to humans as well as animals. ANFs are divided into two categories as heat labile or heat stable on the basis of heat sensitivity. Major ANFs of plant origin are phytic acid, oxalates, tannins, saponins, gossypol, lectins, antivitamin factors, protease inhibitors, amylase inhibitors, metal binding ingredients, goitrogens, etc. (Figure 6.1) . Diets based solely on uncooked or raw plant-based foods like whole grains, legumes, vegetables, and nuts are susceptible to toxic effects of ANFs. Oxalates, for example, are known to bind with calcium and inhibit its absorption in the body. Raw kale, spinach, broccoli, and soybean generally contain oxalates (Savage and

FIGURE 6.1 A brief outline of the adverse effects of major ANFs on humans and animals present in plants (Gemede & Ratta, 2014; Samtiya et al., 2020).

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Klunklin, 2018). The consumption of excessive tannins found in certain fruits is known to inactivate enzymes associated with protein absorption. Phytic acid or phytates are a very important class of ANFs found in cereal grains, legumes, and nuts which are associated with chelation of divalent cations and thus impeding their absorption. Lectins found in tomatoes, brinjals, and peppers are known to cause severe reactions to the body (Pandey et al., 2016). The assimilation of saponins is known to cause enzyme inhibition, red blood cells damage, and intervention in thy­ roid function (Fan et al., 2013).

6.1.2 Antinutrients and Human Health ANFs are generally associated with harmful effects on humans as well as animals; however; documented research also shows certain beneficial effects on humans. The effect of ANF is in general concentration-dependent. ANFs are important active ingredients in several drinks and food. When used at low levels, phytic acid, lectins and phenolic compounds as well as enzyme inhibitors and saponins have reduced blood triglycerides, plasma cholesterols, and blood glucose. Additionally, saponins have role in preventing osteoporosis, maintaining liver function, and preventing plate­ let agglutination (Kao et al., 2008). ANFs like phytic acid, saponins, phenolic com­ pounds, protease inhibitors, phytoestrogens, and lignans of plant origin have roles in reducing the risk of cancers. Tannins are another such compounds found to have a role in probable antibacterial, antiparasitic, and antiviral effects (Lu et  al., 2004; Akiyama et al., 2001; Kolodziej and Kiderlen, 2005). Certain ANFs like lignans and phytoestrogens have been associated with the onset of sterility in humans. Hence, a cautious approach in ascertaining all facets of ANFs, their beneficial effects, concen­ trations for toxic effects, and quantification methods needs to be examined stringently (Popova and Mihaylova, 2019). The aforementioned implies that antinutrients could be valuable tools for managing various diseases. They might not always be harmful even though they lack nutritional value. What is most important is focusing on dosage intake in order to find the bal­ ance between beneficial and hazardous effects of plant bioactives and antinutrients, in addition to the chemical structure, time of exposure, and interaction with other dietary components. Many factors influence their activity. They can both be consid­ ered as ANFs with negative effects or nonnutritive compounds with positive health effects. Consumers’ awareness is crucial, especially when abnormal health conditions are established. There are several approaches to negate harmful effects of ANFs. Modern biotech­ nology’s techniques could reduce the level of certain allergens and anti-nutrients in food. Genome editing biotechnology can create mutations and substitutions in plant and other eukaryotic cells on the basis of nuclease-based forms of engineering such as the TALENS (Transcription Activator-Like Effector Nucleases) or the CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats)/CRISPR-Associated Systems (CAS) (Gaj et al., 2013; Jankele and Svoboda, 2014). Providing an enhanced level of prebiotic in the body can positively influence the effects of anti-nutrients. A classic approach to remove anti-nutrients is to treat the product thermally and use methods such as extrusion, autoclaving, hydro techniques, and enzymatic and harvest treatments (Gibson et al., 2006).

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The nutritional value of foods strongly depends on their nutrients as well as antinutrients composition. This review was designed to focus on the occurrence of antinutrients in wheat, clear their effect on the human body, and commemorate possible paths to disable them. A  major drawback by the consumption of ANFs, especially phytic acid, oxalates etc., present in cereals like wheat and rice is inhibiting the absorp­ tion and assimilation of divalent cations like iron, zinc, magnesium, and calcium. With iron and zinc, malnutrition is of grave concern due to numerous health hazards associated with it, the main being the effects on children and pregnant women.

6.1.3 Anti-Nutritional Factors in Wheat Several ANFs of dietary elements are found in wheat, which might significantly affect the digestibility of wheat items and, hence, influence human health (Table 6.1). Hence, the fundamental focal point of this chapter is to discuss about different anti-nutrient factors present in wheat and furthermore evaluate traditional or advanced handling strategies that can be utilized to diminish the concentration of anti-nutritional factors such as phytate, saponins, polyphenols and protease inhibitors.

6.1.3.1 Phytic Acid (PA) Phytic acid (PA) or phytate is a plant-based secondary metabolite present in seeds of cereals, legumes, peanuts, oilseeds, etc. It is also known as myo inositol-1,2,3,4,5,6­ hexakis dihydrogen phosphate and generally occurs in the range of 0.1 to 6.0% in plants (Lolas, 1976; Garcı́a-Estepa et al., 1999). PA is unstable in its acid form and is typically found as its calcium or calcium magnesium salt (phytate) inside the kernel. As phytate, this compound is thought to represent up to 80% of the phosphorus pres­ ent inside the cereal tissue. Its appropriation varies relying upon the types of plant considered (Gupta et al., 2015). Subsequently, while it is mainly concentrated in the germ of maize, in wheat it occurs mainly in the aleurone layers, and in pearl millet it is distributed throughout the whole kernel. PA acts as an anti-nutrient and shows resistance against the endogenous compounds of the mammalian gastrointestinaldigestive system. The nutritional significance of phytate relies particularly upon both the population and the item they eat. Phytate-sequestration of iron is regarded to be an issue because of complementary food varieties planned for the alleviation of mal­ nourished people (Hurrell et al., 2003). For the production of white bread from wheat, bran and germ layer are removed from wheat kernel and it effectively removes the TABLE 6.1 Content of Few Anti-Nutritional Factors in Wheat S. No.

Anti-Nutrient

Content

Reference

1 2 3 4 5

Tannin Phytic acid Total polyphenols Flavonoids Trypsin inhibitors

1.43–1.83 mg/g 7.95–8.00 mg/g 379 (mg GAE/100 g) 36.3 (mg CAE/100 g) 226.3 mg/g

Singh et al. (2012) Singh et al. (2012) Gunashree et al. (2014) Gunashree et al. (2014) Gunashree et al. (2014)

Source: Popova and Mihaylova (2019); Samtiya et al. (2020)

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phytate present in wheat kernel. In a few cases, phytates contain around 50 to 80% of the total phosphorous in seeds (Lott et al., 2000; Raboy, 2000). The plant-based food sources have more concentration of PA than animal-based foods; and vegetarian diet culture in emerging nations contribute to high ingestion levels (Kwun and Kwon, 2000; Amirabdollahian and Ash, 2010). Studies show that in stomach and small intes­ tine, PA hinders the activity of protein-digesting enzymes (Kies et  al., 2006). PA mainly affects the absorption of minerals and significantly affects children, lactating as well as pregnant women when enormous amount of cereal-based foods are con­ sumed (Al Hasan et al., 2016). During the germination of seeds, a few native enzymes are activated, which degrades PA (Kaukovirta-Norja et al., 2004). In monocotyledons crops like wheat and rice, phytates are present in the bran and aleurone layer and can be removed during processing. In dicotyledons like legumes, oilseeds, and nuts, phytates are found in close relationship with proteins, which decreases the simplicity of division by a basic handling strategy like processing (Sinha and Khare, 2017). PA is a negatively charged structure, which for the most part binds with positively charged divalent ions, for example, Zn, Fe, Mg, and Ca to make complexes and diminishes the absorption of these minerals causing low absorp­ tion rates. Mainly because of this chelating property, PA is considered as an effective anti-nutrient in food varieties and a reason for the deficiency of mineral particles in animals and human nourishment (Grases et al., 2017). Wheat flour contains relatively high levels of PA (600–1,000 mg/kg), while in refined flour, the concentration reduces to 200–400 mg/kg. The concentration of PA is lower in commercially milled flours than in flours produced in a domestic environment (Febles et al., 2002). The role of PA is beneficial as well as shows anti-nutritional effects. Phytate works in a broad pH range as a highly negatively charged ion, and therefore its presence in the diet has a negative impact on the bioavailability of divalent and trivalent mineral ions (such as Zn2+, Fe2+/3+, Ca2+, Mg2+, Mn2+, and Cu2+) (Lönnerdal, 2002; Fredlund et al., 2006).

6.1.3.1.1 Methods for Estimation of Phytic Acid (PA) Several methodologies have been developed to quantify PA content in plants. Precipitation procedures and potentiometric titration are the old-style strategies for PA assessment. With the appearance of innovation, spectroscopy-based (UV-vis, NMR, ICP-OES, ICP-MS, and so on) and sensor-based (electro biosensor and nano­ biosensor) instruments have been utilized to estimate the different types of phytates. Ionic chromatography-based strategy was also developed for the recognition of differ­ ent groups of phosphates including PA and higher inositol phosphates (InsP5-InsP3) in legumes by utilizing an extra purification step bringing about the expulsion of lower inositol phosphates (InsP1 and InsP2) (Burbano et  al., 1995). The initial methods depended on relationship between phytic acid and inorganic phosphorus, as well as that between PA and iron. These techniques were very relentless and needed precision. Later on, profoundly exact techniques like HPLC, SAX-HPLC, capillary electropho­ resis, and NMR spectroscopy were developed (Pandey et al., 2016; Perera et al., 2018). High-performance ion-exchange chromatography (HPIC) has been the best strategy concerning efficiency as well as precision, as it permits the separation of most isomers of inositol phosphates, excluding the stereoisomers. Moreover, a colorimetric strategy (called Wade’s reagent) based on the reaction between iron, sulfosalicylic acid, and PA was developed to estimate the PA in legumes and other food. This test depends on

Wheat-Based Anti-Nutritional Factors

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the principle that there is an inverse relationship between the phosphorus content and interaction between iron and sulfosalicylic acid bringing about a reduction of color intensity with an increase in phosphorus content. Wade’s reagent was applied likewise for the estimation of phytates in differ­ ent kinds of food samples, like corn, soybeans, wheat, sunflower, oats, and rye (Agostinho et al., 2016). Recently, one more colorimetric test based upon the inhi­ bition of color formation by the interaction between glyoxal-bis (2-hydroxianiline) (GBHA) and calcium ions in the presence of PA has been developed. A comparison of different techniques for PA quantification determined that the modified Wade’s measure was simpler, precise, and economical (Gao et al., 2007). In this way, Wade’s measure could be utilized to screen the germplasm and mutant sources of various crops. Methods based upon electrophoresis have also been developed – e.g., capillary isotachophoresis (cITP) was utilized to decide the phytate content in various cereal crops including rice, wheat, barley (Krishnan et  al., 2015), and legumes. In these strategies, the sodium salt forms of the plant extracts were utilized for electropho­ retic partitioning of various groups of phosphates including inositol phosphates and orthophosphate. Capillary zone electrophoresis (CZE) was utilized for phytic acid assessment in soybeans (Perera et al., 2018). Novel techniques with high awareness have been developed that can recognize low phytic acid content. These strategies depend on the concurrent utilization of square wave voltammetry and quick Fourier change (FFT-SWV). Additionally, nano-sensor-based strategies for the recognition of low degrees of PA were also developed.

6.1.3.1.2 Measures for Reducing Phytic Acid Removal of phytic acid increases bioavailability of many cations and thus the nutri­ tional value of meal. There are several methods which have been developed for the removal of phytic acid from grains. The physical methods of PA reduction are discussed later in the chapter. Here, we discuss the genetic and molecular basis of PA reduction. 6.1.3.1.2.1 Application of Phytase Phytase is an enzyme which catalyzes the hydrolysis of phytate to orthophosphate and lower substituted inositol phosphates and further release of chelated cations. It is one of the most effective methods for reduc­ ing PA content in seeds without altering the seed mineral content. Phytase enzyme serves many roles like the removal of phytate in food industries and feed, against environmental phosphorus pollution, promotion of plant growth, and the preparation of special myo-inositol phosphates as tools for biochemical investigation (Greiner and Carlsson 2006; Singh, 2011). Segueilha et al. (1993) used phytase from yeast (S. castelii) to remove PA in wheat bran. Commercially, phytase is added to fish, swine, and poultry feed to enhance the bioavailability of minerals, phosphate, amino acids, and energy. Enzymatic action of phytase on PA releases the bound nutrients, which are otherwise not available for absorption in the digestive tract. Mineral bioavailability is affected by splitting of PA during the process of bread making (Mollgaard,  1946). As a result, bread-making processes are designed with the aim to reduce PA content in the final product. Phytase was isolated commercially from wheat and added to whole-meal wheat flour during bread making, and naturally occurring phytase was activated by soaking and grain malting (Knorr et al., 1981).

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6.1.3.1.2.2 Screening of Micronutrient Dense Germplasm Staple foods of plant origin can be made vitamin- or mineral-rich by using techniques like conventional plant breeding methods or through the use of transgenic techniques. For these tech­ niques, a good amount of genetic variation is required in the germplasm, which can be achieved by utilizing TILLING (Till et  al.,  2007). The technique is efficient in creating a genetically variant population. The transgenic techniques can complement the current breeding efforts and expedite the immediately required biofortified crops to fulfill the nutrition demands of the developing world population. Wheat generally contains a low amount of Fe and Zn (21–32  mg  kg−1 and 15–22  mg  kg−1), respectively (Rawat et  al.,  2009), which is further reduced during the various processing techniques, and hence the bioavailable amount is very low in the finished product with further presence of ANFs. Genetic biofortification tech­ niques are cost-effective, affordable, and generally easily applicable for the intended population. However, the initial requirement of these techniques is the presence of a wide range of genetic variation in the germplasm for the concerned trait like Zn or Fe concentration. Wild and primitive wheat cultivars serve as a much better genetic source of Zn content in comparison to cultivated varieties. A  good variation rang­ ing from around 14 to 190 mg of zinc kg−1 was found in a collection of wild emmer wheat, Triticum turgidum ssp. Dicoccoides. Wild emmer wheat accessions were iden­ tified having a very high Zn content up to 139 mg kg−1, Fe up to 88 mg kg−1, and pro­ tein up to 380 g kg−1 in grains. They were also reported to have high tolerance to Zn deficiency in soil and drought stress (Cantrell and Joppa, 1991; Cakmak et al., 2010). 6.1.3.1.2.3 Molecular Technologies for PA Reduction 6.1.3.1.2.3.1 Production of Mutants with Low Phytic Acid (LPA) Content The LPA varieties can be developed by using advance molecular approaches or silencing of genes involved in the biosynthesis of PA. The method of activity of LPA crops is apparently adjusting the partitioning of phosphorous into inorganic phosphorus (Pi), PA, and inositol phosphates having five or lesser P esters (Raboy, 2002). The LPA mutants overall are not acknowledged straightforwardly to be successful because of the decrease in yield and other undesirable changes. In any case, the hindering changes can be limited through backcross breeding programs. This necessities bet­ ter understanding of hereditary changes in mutants and molecular analysis of LPA traits. Recently, mutants population by compound mutagenesis in the background of high-yielding assortments was also developed – for example, PBW502 and many of the mutants showed low PA level. This is a good source for molecular studies and breeding for decreasing PA content. However, different mutants have been isolated in various cereals; and the hereditary idea of transformations has not been resolved up until this point. In maize, Lpa1 trait was created by altering one of the seven maize myo-inositol phosphate synthase genes that encode MIPS, the enzyme implicated in the underlying step of inositol phosphate biosynthesis. However, sequencing of MIPS gene, that is found adjacent to Lpa1 mutation, showed no lesions inside the coding sequence (Shukla et  al., 2004). Nonlethal recessive mutations that reduce seed PA concentration have been isolated in barley (Larson et al., 1998), maize (Raboy et al., 2000), soybean (Hitz et  al., 2002), rice (Larson et  al., 2000), and wheat (Guttieri et  al., 2004). In rice, LPA mutant was shown to be because of a single recessive mutation on chromosome 2L (Larson et al., 2000). Accordingly, additional markers

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were developed including the region of 47 kb containing eight putative open-reading frames. In wheat, LPA mutants have not been characterized at molecular level up to this point. Henceforth, the development and characterization of LPA mutants in wheat employing Indian wheat cultivars will be a new development. The identification of desirable mutants with LPA and their molecular characterization needs advance study (Ram et al., 2020). 6.1.3.1.2.3.2 Targeting Phytic Acid Pathway Genes The most effective strategy for reduction of PA involves targeting of genes involved in the last steps of PA biosyn­ thesis or transport to its organ of storage, that is, vacuoles (Shi et al., 2003; Aggarwal et  al.,  2018). For this purpose, two major genes IPK1 and ABC C type transporter were identified for targeting. MRP5 gene (ABC transporter) was effectively silenced in soybean with a substantial reduction of PA in the seeds. The effective reduction of PA was found associated with a concomitant increase of Zn and Fe content in seeds. Same strategy was employed and found to be effective in reducing PA content in seeds of maize, beans, and rice (Shi et al., 2007; Panzeri et al., 2011). The same IPK1 gene was effectively silenced in wheat. RNAi-mediated targeting of TaIPK1 gene in wheat resulted in the reduction of PA to the tune of approximately 56% with a concomitant increase in Zn:PA and Fe:PA molar ratios. Therefore, for reduction of PA in wheat, targeting of IPK1 gene for genome editing is a sensible choice (Aggarwal et al., 2018). List of genes targeted in wheat for PA reduction is mentioned in Table 6.2. Owing to allohexaploid nature of wheat genome, transcripts with conserved regions from A, B, and D subgenomes should be considered.

6.1.3.2 Oxalates Oxalic acid forms salts or esters with different minerals such as Ca, K, Fe, Na, and Mg. The K and Na form soluble complexes, while the other minerals form insolu­ ble complexes with oxalic acid. The insoluble salts like calcium oxalate have been mainly responsible for kidney stones because they cannot be excreted out if they reach the urinary tract (Popova and Mihaylova, 2019). By forming these calcium oxalate complexes, oxalate also reduces the uptake of calcium ions. In general, these salts of oxalate possess poor solubility at the intestinal pH (Campos-Vega, Loarca-Piña and Oomah, 2010). Oxalate is not a problem for many people, but, if combined with conditions like primary and enteric hyperoxaluria, the intake of oxalate needs to be reduced. Fermentation or cooking helps in decreasing the concentration of oxalate complexes (Popova and Mihaylova, 2019). Oxalate concentration of the whole grain is found higher than refined flour in case of cereals, especially wheat indicating its TABLE 6.2 List of Genes Targeted for Lowering Phytic Acid (PA) Content in Different Crop Plants Plant species

Targeted gene

Candidate gene

Method used

References

Triticum aestivum Triticum aestivum

TaABCC13 TaIPK1

MRP Inositol pentakisphosphate kinase-1 (IPK-1)

RNAi RNAi

Bhati et al. (2016) Aggarwal et al. (2018)

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primary occurrence in outer layers of grain. Wheat bran has the highest soluble and total oxalate content. In hexaploid wheat T. aestivum, the highest total oxalate content was found in whole meal flour or whole-grain flakes in comparison to the whole grain (Siener et al., 2006). Studies showed that a total oxalate content of whole-wheat flour ranged from 67 to 70 mg/100 g dry matter (DM) (Siener et  al., 2001). In contrast, the total oxalate content of white flour ranged from 16.8 to 45.0 mg/100 g DM while brown rice flour contained 37 mg/100 g DM (Boontaganon et al., 2009). Although, the oxalate content of plants is mainly a species characteristic, considerable variations can occur within the same species depending on the age of the plant, maturity, sea­ son, and soil conditions during growth. Moreover, Siener et al. (2006) compared the soluble and total oxalate contents among cereals and cereal products such as wheat, rye, oat, barley, maize, and rice. The result showed that wheat bran had the highest concentrations (131.2 and 457.4 mg/100 g DM) for soluble and total oxalate contents, respectively, whereas whole-grain rice flakes contained the lowest amount compared to the other whole-grain cereals (soluble oxalate 4.2 mg/100 g DM and 12.2 mg/100 g DM for total oxalates). Therefore, Siener et al. (2006) studied that a high concentration of oxalate was present in the outer layer of cereal grains. Judprasong et  al. (2006) observed that a very low concentration of oxalate was present in whole-grain rice both before and after boiling (12% protein content). The dough is more elastic and stronger after manufacturing of sheet due to higher concentrations of glu­ ten proteins. The glutenin proteins are responsible for the firmness and pliability of gluten or dough. Such proteins promote retention of gas, which raises the volume of baked goods. Hard wheat flours with more than 14% protein are used to make whole­ wheat bread and high protein flour (Dziki and Laskowski, 2005; Pena, 2002).

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FIGURE 7.2 The suitability of different type of wheat for product development.

Durum is the hardest variety of wheat, and semolina made from it is used to make pasta. Due to its hardness and high protein content, durum wheat stands out. Pasta made from durum wheat makes final products with outstanding qualities for cooking and resistance for overcooking (Sissons, 2008). Compared to hard wheat, soft wheat is utilised to create a wide range of products. For the purpose of creating biscuits, it is generally recommended to use soft wheat flours with low damaged starch levels (1.9–3.4%), moderate SDSS volumes (20.0–32.0 mL), and intermediate protein con­ tents (7.9–9.7%) (Dziki and Laskowski, 2005). Dough that is extensible and crumbly but lacking in strength and elasticity is encour­ aged when conditions for manufacturing soft wheat goods’ dough are met, such as add­ ing more sugar and less water. Dough with these characteristics expands more when baked at a higher temperature, producing more biscuits from given dough (Cauvain and Young, 2006; Edmund and Perry, 2008; Kim and Walker, 1992). Higher content of gluten proteins is undesirable for making cake because they prevent dough from spreading and make it more difficult to mould dough into exact dimensions and shapes.

7.3 Existing Milling Technologies and Impact on Nutrients 7.3.1 Milling Technologies The milling process is particularly crucial for the processing of wheat (Bushuk, 1998). Wheat milling is used to produce flour and other products from wheat grains. Before milling, wheat grain is analysed for the gluten content and amylase activity. In order to get flour of similar consistency, the miller may employ blending of different wheat

Wheat Milling and Recent Processing Technologies

227

types together, and this process is known as gristing. Once the grain is analysed and found good for milling, it is further processed using following three steps: 1. Cleaning – Wheat is cleaned to get rid of all the impurities. 2. Conditioning or Tempering – Conditioning or tempering of wheat grains is done by using appropriate moisture and temperature and time. 3. Grinding – It is done to achieve flour of various categories through different milling approaches.

7.3.1.1 Cleaning of Wheat Wheat received at the mill may contain weeds, seeds from other plants, chaff, stones, and other foreign things. Before milling, it must be cleaned. Contaminants and a num­ ber of wheat physical features (weight, size, and density) affect how wheat is cleaned. Cleaning wheat helps remove numerous pollutants. Figure 7.3 represents a flow chart depicting the names of various equipment required for cleaning process. The equipment and processes employed for cleaning are shown in the next sections.

7.3.1.1.1 Separator The vibrating screens of separator remove bits of wood and straw and other items which are too larger or too smaller than wheat.

7.3.1.1.2 Aspirator It makes use of air currents. The foreign matter or impurities which are lighter than wheat are sucked up and removed by strong drafts of air from the aspirator. On an oscillating

FIGURE 7.3 The whole wheat cleaning process.

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Wheat Science

board enclosed in woven wire fabric, the air is pumped through a bed of wheat. A sepa­ ration is achieved using the difference between surface friction and specific gravity.

7.3.1.1.3 Disc Separator It moves the wheat over a number of discs with groves that trap wheat grain-sized par­ ticles of wheat. As objects go across the discs, smaller or larger items are eliminated. Oats, barley, and other foreign ingredients are eliminated.

7.3.1.1.4 Magnetic Separator Metal impurities (iron or steel) are removed from wheat with the help of magnets.

7.3.1.1.5 Scourer It removes dirt, hair, and other debris by rubbing ferociously with the beaters. Wheat is vigorously pushed against perforated steel casings by metal beaters used in scour­ ers. As a result, the majority of the dirt lodged in the wrinkle of the wheat grain is removed and transported by a strong air blast.

7.3.1.1.6 Washer Destoner High-speed spinning of the wheat occurs in the water bath. A  surplus of water is thrown away due to centrifugal force. When stones reach the bottom, they are removed. Only the pure wheat remains after lighter components have drifted away.

7.3.1.2 Conditioning/Tempering of Wheat After cleaning, wheat is conditioned/tempered before milling. Conditioning makes the separation of kernel easy. For this purpose, water is added to kernel to attain desired moisture content. Conditioning toughens the bran layers and causes soft­ ening of the endosperm and, therefore, facilitates wheat milling. Wheat is tem­ pered by placing in bins for 18–72 hours under optimised moisture and temperature conditions. (Liu et al., 2015) reported tempering for 24 hours for hard, mediumhard, and soft wheat at 16%, 15% and 14% moisture contents, respectively. It aids in separating the endosperm from the bran layer and enables complete moisture absorption into the wheat kernel. Moisture can be added at room temperature or at high temperatures (up to 47°C). Preheating, moistening, and cooling are the three stages of the conditioning process in modern mills. Another approach for condi­ tioning is direct steaming. Heating and moistening are done simultaneously in one operation. The temperature of the grain reaches 47°C in around 20 to 30 seconds. The connection between various grain components is broken and made easier to separate by rapid heating. Furthermore, proteins and enzymes show their activities more effectively.

7.3.1.3 Grinding the Wheat For grinding wheat, different milling technologies can be used. As per Liu et  al. (2015), stone milling (SM), roller milling (RM), ultrafine milling (UM), and hammer milling (HM) are the four major milling methods. However, new technologies are also evolving, and jet milling is an example.

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7.3.1.3.1 Stone Milling In this milling process, the original stone abrasion mills for grinding wheat into flour are employed. This is thought of as a standard milling method. These mills employ a range of physical forces, like abrasion, compression, and shear. Stone mills employ chiselled emery stone. A  theoretical extraction rate of 100% is suggested for these mills (Kihlberg et al., 2004). Stone milling is very simple, fast, and the easiest method to make flour from whole wheat (Zhang et al., 2018). It also known as single stream milling. During stone milling, wheat is crumpled between the two stones (Figure 7.4),

FIGURE 7.4 Traditional stone mill.

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and as a result whole-wheat flour with bran, endosperm, middlings, and germ frac­ tions is obtained. In modern systems, composite millstones, connected with metal plates, are being used (Doblado-Maldonado et  al., 2012). One of the plates is fixed, while the other plate rotates. Prabhasankar and Rao (2001) used plate mill, in which plates have about 120 corrugations of 3–4 mm in depth. Electric motors (e.g. 7.5 bhp motor for wheat grinding capacity of 100 kg/h) are used to power these mills. The clean grain is fed into the gap between the two plates using a hopper, where it is sheared and ground into flour by frictional forces. The flour enters through the exit at the bottom of the plate. The stone or plate mill is also known as chakki. Due to the stone mill’s ability to generate whole-wheat flour and consumers’ grow­ ing knowledge of the health advantages of whole wheat, flour making by stone milling has recently undergone a renewal. Further, small entrepreneurs, householders, and food artisans prefer its use due to its simple and cheap process, no grain conditioning requirements (Posner and Hibbs, 2005), and relatively low capital inputs. The major­ ity of the flour produced by stone milling produced particle size less than 85 µm, and about 35% particles were in the size range of >85 µm to 363 µm (Carcea et al., 2020). Irrespective of the wheat type used, stone-milling resulted in a high number of par­ ticles of smaller size range (1,000 μm) and fine particles (